Cumulative Final ExamYour response has been submitted successful.docx

Cumulative Final Exam
Your response has been submitted successfully.
Points Awarded
95
Points Missed
5
Percentage
95%
1.
A description of different houses for sale includes the following
variables. Which of the variables is categorical?
A.
the square footage of the house
B.
whether or not the house has a finished basement
C.
the monthly electric bill
D.
All of the above
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
2.
As part of a data base on new births at a hospital, some
variables recorded are the age of the mother, marital status of

the mother (e.g., single, married, divorced), weight of the baby,
and sex of the baby. Of these variables
A.
the individuals described are mothers and babies involved in
births at a hospital.
B.
age of mother and weight of baby are quantitative variables.
C.
sex and marital status are categorical variables.
D.
All of the above.
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
3.
A large university is divided into six colleges, with most
students graduating from four of these colleges. The following
bar chart gives the distribution of the percent graduating from
the four most popular colleges in 2003.
Reference: Ref 1-2
Which of the following is a correct statement?
A.
A timeplot of the 2003 distribution would be more informative.
B.
The bar graph is skewed to the right.

C.
The bar graph is skewed to the left.
D.
It would be correct to make a pie chart if you added an “Other”
category.
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
4.
The histogram below shows the time visitors to a museum spent
browsing an exhibit on a Saturday. There were 300 visitors that
day. The following histogram is of the data collected.
Reference: Ref 1-3
The histogram
A.
is skewed right.
B.
has an outlier.
C.
is asymmetric.
D.
All of the above
Correct
Points Earned:

1/1
Correct Answer:
D
Your Response:
D
5.
The stemplot below displays midterm exam scores for the 34
students taking a Calculus course. The highest possible test
score was 100. The teacher declared that an exam grade of 65 or
higher was good enough for a grade of “C” or better.
Reference: Ref 1-5
The percent of students earning a grade of “C” or higher (as
declared by the teacher) is closest to
A.
35%.
B.
50%.
C.
65%.
D.
80%.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
6.
A stemplot of ages of 18 faculty members in a college math

department follows. 4|3 represents 43 years.
Reference: Ref 2-2
The median age (in years) of the faculty members at
Wilmington State is
A.
39.
B.
45.
C.
47.5.
D.
49.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
7.
The exam scores (out of 100 points) for all students taking an
introductory Statistics course are used to construct the
following boxplot.
Reference: Ref 2-3
If each person increased his or her score by 5 points then
A.

the third quartile would increase by 5 points.
B.
the median score would increase by 5 points.
C.
the interquartile range would remain unchanged.
D.
All of the above.
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
8.
The histogram below shows the average property damage in
millions of dollars caused by tornadoes over a 50-year period in
each of the states and Puerto Rico.
Reference: Ref 2-6
From the histogram, the first quartile must be
A.
in the interval 0–10.
B.
C.
D.
greater than 10.
Correct

Points Earned:
1/1
Correct Answer:
A
Your Response:
A
9.
The average salary of all female workers at a large plant is
$35,000. The average salary of all male workers at the plant is
$41,000. If there are more female workers than female workers
at the plant, then the average salary at the plant must be
A.
exactly $38,000.
B.
larger than $38,000.
C.
smaller than $38,000.
D.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
10.
A group of 4 friends has median age 22. Three of them are aged
20, 18, and 24. The age of the fourth friend must be
A.
22.

B.
24 or older.
C.
18 or younger.
D.
None of the above – we can't tell from the information
provided.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
11.
Do men with more children have higher blood pressure? In a
study, blood pressures of men with more than three children
were compared with those of men with three or fewer children.
Which of the following is true for this study?
A.
The response variable is blood pressure.
B.
The explanatory variable is blood pressure.
C.
The explanatory variable is number of children (“more than
three” vs. “three or fewer”).
D.
Both a and c
Correct
Points Earned:
1/1

Correct Answer:
D
Your Response:
D
12.
Archaeologists often find only parts of ancient human remains.
For example, they may find a small finger bone, called the
metacarpal bone. Is it possible to predict the height of a human
from the length of his or her metacarpal bone? To investigate, a
researcher measures the heights and metacarpal lengths of 200
adults. In making the scatterplot, the researcher should
A.
plot the height of the person on the horizontal axis.
B.
plot the metacarpal length on the horizontal axis.
C.
first determine if the heights of humans follow a Normal
distribution.
D.
use a plotting scale that makes the overall trend roughly linear.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
13.
For each menu item at a fast food restaurant, fat content (in
grams) and number of calories were recorded. A scatterplot of
these data is given:

Reference: Ref 4-3
Suppose we changed the units of fat from grams to ounces.
Which of the following statements is correct?
A.
The new scatterplot would look a bit different, and the new
correlation would be smaller.
B.
The new scatterplot would look a bit different, but the
correlation would be unchanged.
C.
The new scatterplot would be unchanged and so would the
correlation.
D.
The new scatterplot would be unchanged, but the new
correlation will be smaller.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
14.
Which of the following is true of the correlation coefficient r?
A.
Multiplying all data values (x's and y's) by 20 will have no
impact on r.
B.
–1 r +1.
C.
If r = 0, then there is no linear relationship between x and y.

D.
All of the above
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
15.
Use the following density curve to answer the question(s)
below.
Reference: Ref 3-1
For this density curve, the third quartile is
A.
0.5.
B.
0.75.
C.
1.5.
D.
1.75.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:

C
16.
Using the standard Normal distribution tables, the area under
the standard Normal curve corresponding to Z > –1.62 is
A.
0.0044.
B.
0.0526.
C.
0.9474.
D.
0.9956.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
17.
A locomotive's “adhesion” is the locomotive's pulling force as a
multiple of its weight. This is an important performance
measure of a locomotive. A diesel locomotive model has
adhesion that varies in actual use according to a Normal
distribution with mean 0.37 and standard deviation 0.04.
Reference: Ref 3-3
The first quartile for the adhesion distribution is
A.
0.04.
B.
0.25.

C.
0.29 hours.
D.
0.34 hours.
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
18.
A company produces packets of soap powder labeled “Giant
Size 32 Ounces.” The actual weight of soap powder in such a
box has a Normal distribution with a mean of 33 oz and a
standard deviation of 0.7 oz. To avoid having dissatisfied
customers, the company says a box of soap is considered
underweight if it weighs less than 32 oz. To avoid losing
money, it labels the top 5% (the heaviest 5%) overweight.
Reference: Ref 3-6
What proportion of boxes is underweight (i.e., weigh less than
32 oz)?
A.
.0764
B.
.2420
C.
.7580
D.
.9236
Correct

Points Earned:
1/1
Correct Answer:
A
Your Response:
A
19.
A market research company employs a large number of typists
to enter data into a computer database. The time taken for new
typists to learn the computer system is known to have a Normal
distribution with a mean of 130 minutes and a standard
deviation of 20 minutes. A candidate is automatically hired if he
or she learns the computer system in less than 100 minutes. A
cut-off time is set at the slowest 40% of the learning
distribution. Anyone slower than this cut-off time is not hired.
Reference: Ref 3-7
What proportion of candidates will be automatically hired?
A.
0.023
B.
0.067
C.
0.159
D.
0.309
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:

B
20.
Scores on the SAT verbal test in recent years follow
approximately the N(515, 109) distribution.
Reference: Ref 3-8
The proportion of students scoring between 460 and 550 is
closest to
A.
0.309.
B.
0.317.
C.
0.626.
D.
0.681.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
21.
The least-squares regression line is
A.
the line that passes through the most data points.
B.
the line that makes the sum of the squares of the vertical
distances of the data points from the line (the sum of squared
residuals) as small as possible.
C.

the line such that half of the data points fall above the line and
half fall below the line.
D.
All of the above
Incorrect
Points Earned:
0/1
Correct Answer:
B
Your Response:
D
22.
A researcher wants to determine whether the rate of water flow
(in liters per second) over an experimental soil bed can be used
to predict the amount of soil washed away (in kilograms). The
researcher measures the amount of soil washed away for various
flow rates, and from these data calculates the least-squares
regression line to be
amount of eroded soil = 0.4 + 1.3 × (flow rate)
The correlation between amount of eroded soil and flow rate
would be
A.
1/1.3.
B.
1.3.
C.
positive, but we cannot say what the exact value is.
D.
either positive or negative. It is impossible to say anything
about the correlation from the information given.

Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
23.
Suppose we fit the least-squares regression line to a set of data.
Points with unusually large values of the residuals are called
A.
response variables.
B.
the slope.
C.
outliers.
D.
correlated.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
24.
The correlation between the height and weight of children aged
6 to 9 is found to be about r = 0.8. Suppose we use the
height x of a child to predict the weight y of the child. We
conclude
A.

the least-squares regression line of y on x would have a slope of
0.8.
B.
about 80% of the time, age will accurately predict weight.
C.
height is generally 80% of a child's weight.
D.
the fraction of variation in weights explained by the least-
squares regression line of weight on height is 0.64.
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
25.
The following is a scatterplot for profits versus sales (in tens of
thousands of dollars) for a sample of 14 large companies. The
correlation between Sales and Profits is 0.949.
Reference: Ref 5-3
From this information we see
A.
there is a very influential observation in the data.
B.
there is a clear error because profits cannot be negative.
C.
profits can be accurately predicted from sales.
D.
All of the above

Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
26.
Curiously, during months when sales of beer are above average,
sales of ice cream also tend to be above average; during months
when sales of beer are below average, sales of ice cream also
tend to be below average. Which of the following can we
conclude from these facts?
A.
The correlation between “beer sales” and “ice cream sales” is
negative.
B.
For a lot of people, drinking beer causes a desire for ice cream,
or vice versa.
C.
A scatterplot of monthly ice cream sales vs. monthly beer sales
would show that a straight line describes the pattern in the plot,
but it would have to be a horizontal line.
D.
None of the above.
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D

27.
A newspaper article is summarized: According to a new study,
teachers may be more inclined to give higher grades to students,
hoping to gain favor with the university administrators who
grant tenure. The study examined the average grade and
teaching evaluation in a large number of courses given in 1997
in order to investigate the effects of grade inflation on
evaluations. “I am concerned with student evaluations because
instruction has become a popularity contest for some teachers,”
said Professor Smith, who recently completed the study. Results
showed higher grades directly corresponded to a more positive
evaluation.
Reference: Ref 5-4
Which of the following would be a valid conclusion to draw
from the study?
A.
A teacher can improve their teaching evaluations by giving
higher grades.
B.
A good teacher, as measured by teaching evaluations, helps
students learn better and this results in higher grades.
C.
Teachers of courses in which the mean grade is above average
apparently tend to have above average teaching evaluations.
D.
All of the above.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:

C
28.
A survey of undergraduate college students at a small university
was recently done by an administrator in charge of residential
life services. A random sample of 300 students was selected
from each class level (freshman, sophomore, junior, senior).
Each student was asked to complete and return a short
questionnaire on quality of campus residence. Some students
returned the questionnaire, and some didn't. This is summarized
in the table below:
Class
Returned
Not response
Total
Freshman
110
190
300
Sophomore
130
170
300
Junior
170
130
300
Senior
160
140
300
Reference: Ref 6-1
Which of the following conclusions seems to be supported by
the data?

A.
Juniors and seniors appear to be more likely to return the survey
than freshmen and sophomores.
B.
Juniors and seniors are happier with the quality of campus
residences than freshman and sophomores.
C.
Students that did not return the questionnaire are unhappy with
the quality of campus residences.
D.
The percentage of students returning the questionnaire is the
same for each class.
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
29.
The following table describes the opinions of 570 people.
Students were classified by class (freshman, sophomore, junior,
or senior), and by their opinion of campus residence quality
(high quality, medium quality, low quality).
Class
High
Medium
Low
Total
Freshman
65
25
20

110
Sophomore
55
30
45
130
Junior
60
40
70
170
Senior
30
60
70
160
Total
210
155
205
570
Reference: Ref 6-2
Of the students that feel campus residences are of high quality,
what percent are seniors?

A.
14.3%
B.
18.8%
C.
28.1%
D.
33.3%
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
30.
In a study of the link between high blood pressure and
cardiovascular disease, a group of white males aged 35 to 64
was followed for five years. At the beginning of the study, each
man had his blood pressure measured and it was classified as
either “low” systolic blood pressure (less than 140 mm Hg) or
“high” blood pressure (140 mm Hg or higher). The following
table gives the number of men in each blood pressure category
and the number of deaths from cardiovascular disease during the
five-year period.
Blood pressure
Deaths
Total
Low
10

2000
High
50
3500
Based on these data, which of the following statements is
correct?
A.
These data are consistent with the idea that there is a link
between high blood pressure and death from cardiovascular
disease.
B.
The mortality rate (proportion of deaths) for men with high
blood pressure is five times that of men with low blood
pressure.
C.
These data probably understate the link between high blood
pressure and death from cardiovascular disease since men will
tend to understate their true blood pressure.
D.
All of the above
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
31.
Sickle-cell disease is a painful disorder of the red blood cells
that in the United States affects mostly blacks. To investigate
whether the drug hydroxyurea can reduce the pain associated

with sickle-cell disease, a study by NIH gave the drug to 150
sickle-cell sufferers and the placebo to another 150. Neither
doctors nor patients were told who received the drug. The
number of episodes of pain reported by each subject was
recorded. This is an example of
A.
an observational study.
B.
an experiment, but not a double-blind experiment.
C.
a double-blind experiment.
D.
a paired data experiment.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
32.
In order to investigate treatments for morbid obesity, obese
subjects satisfying fairly strict requirements were randomly
assigned to one of three groups: gastric bypass surgery;
participation in a diet and exercise program; or both gastric
bypass surgery and participation in the diet and exercise
program. Researchers carefully observed the amount of weight
lost five years after the study began.
Reference: Ref 9-1
This study has
A.

four factors.
B.
three treatments.
C.
two treatments.
D.
None of the above
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
33.
A researcher studying the effect of price cuts on consumers'
expectations makes up two different histories of the store price
of a hypothetical brand of laundry detergent for the past year.
Eight students in a class view one or the other price history on a
computer. Some students see a steady price, while others see
regular sales that temporarily cut the price. Students are asked
the price they would expect to pay.
Reference: Ref 9-2
This is an example of
A.
a matched pairs experiment.
B.
a two-factor design.
C.
a randomized comparative experiment.
D.
a randomized observational study.

Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
34.
A researcher finds 2000 mildly overweight women who exercise
regularly, have not had a heart attack, and are willing to
participate in the study. She randomly assigns 500 of the women
to take an appetite suppressant. The other 500 women are given
a placebo. Both groups are followed for five years and the
amount of weight lost after this time is recorded.
Reference: Ref 9-4
The factor in the experiment is
A.
the weight lost by women in the study.
B.
use of a control group taking a placebo.
C.
the treatment taken by women in the study — appetite
suppressant or placebo.
D.
the length of the study.
Correct
Points Earned:
1/1
Correct Answer:
C

Your Response:
C
35.
Medical researchers are excited about a new cancer treatment
that destroys tumors by cutting off their blood supply. To date,
the treatment has only been tried on mice, but in mice it has
been nearly 100% effective in eradicating tumors and appears to
have no side effects. As evidence of the effectiveness of the
new treatment in treating cancer in humans, these studies
A.
display a high degree of statistical significance, and so with
nearly 100% certainty will work in humans.
B.
are convincing, assuming the results have been replicated in a
large number of mice.
C.
are convincing, assuming that proper randomization and control
were used.
D.
suffer from lack of realism.
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
36.
Each month, the census bureau mails survey forms to 250,000
households asking questions about the people living in the
household and about such things as motor vehicles and housing
costs. Telephone calls are made to households that don't return
the form. In one month, responses were obtained from 240,000

of the households contacted.
Reference: Ref 8-1
The population of interest is
A.
the residents in the suburb that support the new recreation
center.
B.
the 250,000 households contacted.
C.
only U.S. households with phones.
D.
all U.S. households.
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
37.
Import customs officials sometimes randomly select crates of
cargo for close, but time-consuming, inspection. Suppose there
are nine crates of cargo from the following companies, and
customs officials will randomly select four for close
inspection.
1. Ravenburg
4. Dallhoise
7. Cherryport
2. Corsair
5. Baggate
8. Foxwood
3. Sapphire

6. Strommond
9. Bamboro
To do this, use the numerical labels attached to the previous
names and the following list of random digits. Read the list of
random digits from left to right, starting at the beginning of the
list.
748803 12009 45287 71753 98236 66419 84533 11793 20495
05907 11384
Reference: Ref 8-4
The simple random sample is
A.
7488.
B.
7483.
C.
Cherryport, Dallhoise, Foxwood, and Sapphire.
D.
Cherryport, Foxwood, Bamboro, and Strommond.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
38.
The magazine High Times has a website that once asked visitors
whether recreational marijuana use should be legal. This is an
example of

A.
voluntary response sampling.
B.
a survey with little bias because a large SRS was used.
C.
a survey with little bias since someone who responded would
know his or her opinion.
D.
All of the above
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
39.
Advice columnist Ann Landers once asked her readers with
children to answer the following question: “If you had it to do
over again, would you have children?” Readers were invited to
send a response to this question by mail. Of the approximately
10,000 responses Landers received, approximately 70% said
“no.”
Reference: Ref 8-5
The sample is
A.
the approximately 10,000 readers who wrote in.
B.
the approximately 70% of women who answered “no.”
C.
the respondents that regretted having children.
D.

all readers.
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
40.
A public opinion poll in Ohio wants to determine whether
registered voters in the state approve of a measure to ban
smoking in all public areas. The researchers select a simple
random sample of 50 registered voters from each county in the
state and ask whether they approve or disapprove of the
measure. This is an example of
A.
a systematic county sample.
B.
a stratified sample.
C.
a multistage sample.
D.
a simple random sample.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
41.

The law of large numbers states that as the number of
observations drawn at random from a population with finite
mean μ increases, the mean of the observed values
A.
gets larger and larger.
B.
gets smaller and smaller.
C.
tends to get closer and closer to the population mean μ.
D.
fluctuates steadily between one standard deviation above and
one standard deviation below the mean.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
42.
Suppose you want to estimate the average number of sick days
taken by all employees at a large company during a year.
Suppose (unknown to you) this is 4 days. You devise a way to
randomly select 200 employees for a survey and use the sample
mean number of sick days as an estimate of the population mean
for all workers at the company. Unknown to you, the sampling
distribution of the sample mean has an average value of 4.8.
This means that
A.
your estimator (the sample mean) is not an unbiased estimator
of the population mean because your sampling method tends to
pick people that take more sick days.

B.
your estimator is an unbiased estimator of the population mean.
C.
if you survey more American adults, your sample mean will
tend to get closer to the population mean.
D.
None of the above
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
43.
A statistic is said to be unbiased if
A.
the person computing it doesn't favor any particular outcome.
B.
the mean of its sampling distribution is equal to the true value
of the parameter being estimated.
C.
both the person who calculated the statistic and the subjects
whose responses make up the statistic were truthful.
D.
it is used for only honest purposes.
Correct
Points Earned:
1/1
Correct Answer:
B

Your Response:
B
44.
Suppose a large population has mean μ and standard
deviation σ, and a simple random sample of size n is taken. The
sampling distribution of the sample mean has mean and
variance respectively equal to
A.
μ/n and σ2/n.
B.
μ and σ/n.
C.
μ/n and σ2/n2.
D.
μ and σ2/n.
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
45.
A manufacturing process produces bags of cookies. The
distribution of content weights of these bags is Normal with
mean 16.0 oz and standard deviation 0.8 oz. We will randomly
select n bags of cookies and weigh the contents of each bag
selected.
Reference: Ref 11-8
How many bags should be selected so that the standard
deviation of the sample mean is 0.1 ounces?

A.
8 bags
B.
10 bags
C.
64 bags
D.
100 bags
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
46.
selected.
Reference: Ref 11-8
If 100 bags of cookies are selected randomly, the probability
that the sample mean will be between 15.84 and 16.16 ounces is
A.
0.046.
B.
0.110.
C.
0.890.
D.
0.954.

Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
47.
You randomly select 500 students and observe that 85 of them
smoke. Estimate the probability that a randomly selected
student smokes.
A.
0.27
B.
0.50, since there are two possible outcomes for every student
surveyed (smoke, don't smoke)
C.
0.17
D.
1.2
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
48.
A North American roulette wheel has 38 slots, of which 18 are
red, 18 are black, and 2 are green.
Reference: Ref 10-1

If you bet on red, the probability of winning is 18/38 = 0.4737.
The probability 0.4737 represents
A.
the fact that you're more likely to win betting on red than you
are to lose.
B.
the proportion of times this event will occur in a very long
series of individual bets on red.
C.
the fact that if you make 100 wagers on red, you'll have 47 or
48 wins.
D.
nothing important, since every spin of the wheel results in one
of three outcomes (red, black, or green).
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
49.
According to the Current Population Survey, the following table
summarizes probabilities for randomly selecting a full-time
student in various age groups:
Age
15-17
18-24
25-34
35 or older
Probability
0.007

0.573
0.260
0.160
Reference: Ref 10-3
If we randomly select a full-time student, what is the
probability that he/she is 25 or older?
A.
0.260
B.
0.420
C.
0.740
D.
Impossible to determine from the information given.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
50.
You roll a pair of fair dice and compute the number of spots on
the two sides facing up. Denote this total by X. The probability
distribution of X is
Reference: Ref 10-9
The probability that X is a 2, 11, or 12 is

A.
1/36.
B.
2/36
C.
3/36.
D.
4/36.
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
51.
A set of 20 cards consists of 12 red cards and 8 black cards. The
cards are shuffled thoroughly and you choose one at random,
observe its color, and replace it in the set. The cards are
thoroughly reshuffled, and you again choose a card at random,
observe its color, and replace it in the set. This is done a total
of six times. Let X be the number of red cards observed in these
six trials. The variance of X is
A.
6.
B.
3.60.
C.
2.4.
D.
1.44.
Correct

Points Earned:
1/1
Correct Answer:
D
Your Response:
D
52.
In an instant lottery, your chances of winning are 0.1. If you
play the lottery five times and outcomes are independent, the
probability that you win at most once is
A.
0.081.
B.
0.100.
C.
0.919.
D.
0.954.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
53.
If X has a binomial distribution with 20 trials and a mean of 6,
then the success probability p is
A.
0.30.
B.

0.50.
C.
0.75.
D.
This cannot be determined without taking a sample.
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
54.
At a large Midwestern college, 4% of the students are Hispanic.
A random sample of 20 students from the college are selected.
Let X denote the number of Hispanics among them.
Reference: Ref 13-2
The mean of X is
A.
0.4.
B.
0.8.
C.
1.2.
D.
1.6.
Correct
Points Earned:
1/1
Correct Answer:

B
Your Response:
B
55.
An article in Parenting magazine reported that 60% of
Americans needed a vacation after visiting their families for the
holidays. Suppose this is the true proportion of Americans who
feel this way. A random sample of 100 Americans is taken.
What is the probability that less than 50% of the people in the
sample feel that they need a vacation after visiting their
families for the holidays?
A.
0.4000
B.
0.1446
C.
0.0207
D.
0.0062
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
56.
A system has two components that operate in parallel, as shown
in the following diagram. Because the components operate in
parallel, at least one of the components must function properly
if the system is to function properly. The probabilities
of failures for the components 1 and 2 during one period of
operation are 0.20 and 0.03, respectively. LetF denote the event

that component 1 fails during one period of operation
and G denote the event that component 2 fails during one period
of operation. The component failures are independent.
Reference: Ref 12-3
The probability that the system functions properly during one
period of operation is closest to
A.
0.994.
B.
0.970.
C.
0.940.
D.
0.776.
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
57.
Spelling mistakes in a text are either “nonword errors” or “word
errors.” A nonword error produces a string of letters that is not
a word, such as “the” typed as “teh.” Word errors produce the
wrong word, such as “loose” typed as “lose.” Nonword errors
make up 25% of all errors. A human proofreader will catch 80%
of nonword errors and 50% of word errors.
Reference: Ref 12-4
What percent of errors will the proofreader catch?

A.
0.20
B.
0.375
C.
0.575
D.
0.80
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
58.
The following table gives the sex and age group of college
students at a Midwestern university.
Female
Male
Total
15 to 17 years
89
61
150
18 to 24 years
5,668
4,697
10,365
25 to 34 years
1,904
1,589

3,493
35 years or older
1,660
970
2,630
Total
9,321
7,317
16,638
A student is to be selected at random.
Reference: Ref 12-5
The probability that the selected student is a female that is 15 to
17 years old is
A.
0.005.
B.
0.010.
C.
0.560.
D.
0.593.
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
59.
In a particular game, a fair die is tossed. If the number of spots
showing is a six, you win $6, if the number of spots showing is

a five, you win $3, if the number of spots showing is 4, you win
$2, and if the number of spots showing is 3, you win $1. If the
number of spots showing is 1 or 2, you win nothing. You are
going to play the game twice.
Reference: Ref 12-6
The probability that you win at least $9 in total on the two plays
of the game is
A.
1/6.
B.
1/3.
C.
1/36.
D.
1/12.
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
60.
Event A occurs with probability 0.3, and event B occurs with
probability 0.4. If A and B are independent, we may conclude
A.
P(A and B) = 0.12.
B.
P(A|B) = 0.3.
C.
P(B|A) = 0.4.

D.
All of the above
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
61.
The upper 0.05 critical value of the standard Normal
distribution is
A.
1.645.
B.
1.960.
C.
2.326.
D.
2.576.
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
62.
In formulating hypotheses for a statistical test of significance,
the null hypothesis is often

A.
a statement of “no effect” or “no difference.”
B.
the probability of observing the data you actually obtained.
C.
a statement that the data are all 0.
D.
0.05.
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
63.
You measure the lifetime of a random sample of 64 tires of a
certain brand. The sample mean is = 50 months. Suppose that
the lifetimes for tires of this brand follow a normal distribution,
with unknown mean μ and standard deviation σ = 5 kg.
Reference: Ref 14-2
Suppose I had measured the lifetimes of a random sample of
100 tires rather than 64. Which of the following statements is
true?
A.
The margin of error for our 99% confidence interval would
increase.
B.
decrease.
C.
The margin of error for our 99% confidence interval would stay

the same since the level of confidence has not changed.
D.
σ would decrease.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
64.
Is the mean age at which American children can first read now
under 4 years? If the population of all American children has
mean age of μ years until they begin to read, one would test
which of the following null and alternative hypotheses to
answer this question?
A.
H0: μ = 4 vs. Ha: μ > 4
B.
H0: μ = 4 vs. Ha: μ < 4
C.
H0: μ = 4 vs. Ha: μ ≠ 4
D.
H0: μ = 4 vs. Ha: μ = 4 ± , assuming our sample size is n
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B

65.
The Survey of Study Habits and Attitudes (SSHA) is a
psychological test that measures the motivation, attitudes, and
study habits of college students. Scores range from 0 to 200 and
follow (approximately) a Normal distribution, with mean of 110
and standard deviation σ = 20. You suspect that incoming
freshman have a mean μ, which is different from 110 because
they are often excited yet anxious about entering college. To
verify your suspicion, you test the hypotheses
H0: μ = 110, Ha: μ 110
You give the SSHA to 50 students who are incoming freshman
and find their mean score.
Reference: Ref 15-1
The P-value of the test of the null hypothesis is
A.
the probability, assuming the null hypothesis is true, that the
test statistic will take a value at least as extreme as that actually
observed.
B.
the probability, assuming the null hypothesis is false, that the
test statistic will take a value at least as extreme as that actually
observed.
C.
the probability the null hypothesis is true.
D.
the probability the null hypothesis is false.
Correct
Points Earned:
1/1
Correct Answer:
A

Your Response:
A
66.
To assess the accuracy of a laboratory scale, a standard weight
known to weigh 1 gram is repeatedly weighed a total of n times,
and the mean of the weighings is computed. Suppose the scale
readings are Normally distributed, with unknown mean m and
standard deviation σ = 0.01 g. How large should n be, so that a
95% confidence interval for mhas a margin of error of ±
0.0001?
A.
100
B.
196
C.
10,000
D.
38,416
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
67.
A company produces precision 1 meter (1000 mm) rulers. The
actual distribution of lengths of the rulers produced by this
company is Normal, with mean μ and standard deviationσ =
0.02 mm. Suppose I select a simple random sample of four of
the rulers produced by the company and I measure their lengths
in mm. The results of these four measurements are

1000.01
999.98
1000.00
1000.01.
Based on these data, a 90% confidence interval for μ is
A.
1000.00 ± 0.0082.
B.
1000.00 ± 0.0115.
C.
1000.00 ± 0.0165.
D.
1000.00 ± 0.0196.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
68.
H0: μ = 110, Ha: μ 110

Reference: Ref 15-1
If you observe a sample mean of = 115.35, what is the
corresponding P-value?
A.
0.058
B.
0.029
C.
0.787
D.
None of the above
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
69.
The time (in number of days) until maturity of a certain variety
of tomato plant is Normally distributed with mean μ and
standard deviation σ = 2.4. I select a simple random sample of
four plants of this variety and measure the time until maturity.
The four times, in days, are
63
69
62
66
Reference: Ref 14-3

If I wanted the margin of error for the 95% confidence interval
to be ± 1 inch, I should select a simple random sample of size
A.
5.
B.
7.
C.
23.
D.
39.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
70.
A level α two-sided significance test does not reject the null
hypothesis H0:μ = μ0 when
A.
the z test statistic differs from μ0.
B.
the value μ0 falls inside a level 1-α confidence interval for μ.
C.
the z test statistic differs from μ.
D.
the value μ0 falls outside a level 1-α confidence interval for μ.
Correct
Points Earned:

1/1
Correct Answer:
B
Your Response:
B
71.
An SRS of 18 recent birth records at the local hospital was
selected. In the sample, the average birth weight was 119.6
ounces and the standard deviation was 6.5 ounces. Assume that
in the population of all babies born in this hospital, the birth
weights follow a Normal distribution, with mean μ.
Reference: Ref 18-1
We are interested in a 95% confidence interval for the
population mean birth weight. The margin of error associated
with the confidence interval is
A.
6.50 ounces.
B.
3.23 ounces.
C.
3.003 ounces.
D.
0.76 ounces.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
72.
In assessing the validity of any test of hypotheses, it is good

practice to
A.
examine the probability model by using exploratory data
analysis on the data.
B.
test the hypotheses at several different levels of significance.
C.
test both one- and two-sided hypotheses to help guarantee
consistency.
D.
All of the above
Incorrect
Points Earned:
0/1
Correct Answer:
A
Your Response:
D
73.
The height (in inches) of males in the United States is believed
to be Normally distributed, with mean μ. The average height of
a random sample of 50 American adult males is = 69.72 inches,
and the standard deviation of the 50 heights is s = 4.23. The
standard error of is
A.
0.084.
B.
0.357.
C.
0.598.
D.
0.731.

Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
74.
Does 30 minutes of meditation every day provide significant
improvement in mental performance? To investigate this issue,
a researcher conducted a study with 150 adult subjects who
meditated for 30 minutes each day for a period of six months.
At the end of the study, 300 variables related to the mental
performance of the subjects were measured on each subject and
the means compared to known means for these variables in the
population of all adults. Sixteen of these variables were
significantly better (in the sense of statistical significance) at
the α = 0.05 level for the group that performed 30 minutes of
meditation each day as compared to the population as a whole,
and three variables were significantly better at the α = 0.01
level for the group that performed 30 minutes of meditation
each day as compared to the population as a whole. It would be
correct to conclude that
A.
there is very good statistical evidence that 30 minutes of
meditation each day provides some improvement in mental
performance.
B.
there is very good statistical evidence that 30 minutes of
meditation each day provides improvement for the variable that
was significant at the α = 0.01 level. We should be somewhat
cautious about making claims for the variables that were
significant at the α = 0.05 level.

C.
these results would have provided very good statistical evidence
that 30 minutes of meditation each day provides some
improvement in mental performance if the number of subjects
had been larger. It is premature to draw statistical conclusions
from studies in which the number of subjects is less than the
number of variables measured.
D.
None of the above
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
75.
A Type I error is
A.
rejecting the null hypothesis when it is true.
B.
accepting the null hypothesis when it is false.
C.
incorrectly specifying the null hypothesis.
D.
incorrectly specifying the alternative hypothesis.
Correct
Points Earned:
1/1
Correct Answer:
A

Your Response:
A
76.
The reduction in cholesterol level after eating a certain brand of
oatmeal for breakfast for one month in people with cholesterol
levels over 200 is Normally distributed, with mean (in
milligrams) μ and standard deviation σ = 8. Although the brand
advertises that eating their oatmeal for breakfast daily for one
month will produce a mean decrease in cholesterol of more than
20 points for people with cholesterol levels over 200, you
believe that the mean decrease in cholesterol is actually less
than advertised. To explore this, you test the hypotheses
H0: μ = 20, Ha: μ < 20
at the 0.05 level. You will do this by randomly selecting 144
people with cholesterol levels over 200 and, after eating this
brand of oatmeal for one month, computing the mean
decrease in cholesterol levels of the subjects. If you observe a
sample mean cholesterol reduction of = 18.52, the P-value
obtained is
A.
between 0.05 and 0.10.
B.
C.
D.
less than 0.01.
Correct
Points Earned:
1/1
Correct Answer:
C

Your Response:
C
77.
Which of the following will reduce the value of the power in a
statistical test of hypotheses?
A.
Decrease the type II error probability.
B.
Decrease the sample size.
C.
Reject the null hypothesis only if the P-value is smaller than the
level of significance.
D.
All of the above
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
78.
A special diet is intended to reduce systolic blood pressure. If
the diet is effective, the target is to have the average systolic
blood pressure of this group be below 150. After six months on
the diet, an SRS of 28 patients with high blood pressure had an
average cholesterol of = 143, with standard deviation s = 21. Is
this sufficient evidence that the diet is effective in meeting the
target? Assume the distribution of the cholesterol for patients in
this group is approximately Normal with mean μ.
Reference: Ref 18-2
A 95% confidence interval for the average blood pressure of all

similar patients who have been on the diet for 6 months is
A.
143 ± 21.
B.
143 ± 7.78.
C.
143 ± 8.14.
D.
143 ± 1.54.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
79.
We wish to see if, on average, traffic is moving at the posted
speed limit of 65 miles per hour along a certain stretch of
Interstate 70. On each of four randomly selected days, a
randomly selected car is timed and the speed of the car is
recorded. The observed speeds are 70, 65, 70, and 75 miles per
hour. Assuming that speeds are Normally distributed with
mean μ, we test whether, on average, traffic is moving at 65
miles per hour, by testing the hypotheses
H0: μ = 65, Ha: μ ≠ 65.
Reference: Ref 18-3
Based on the data, the value of the one-sample t statistic is
A.
5.

B.
4.90.
C.
2.45.
D.
1.23.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
80.
The water diet requires one to drink two cups of water every
half hour from when one gets up until one goes to bed, but
otherwise allows one to eat whatever one likes. Four adult
volunteers agree to test the diet. They are weighed prior to
beginning the diet and after six weeks on the diet. The weights
(in pounds) are
Person
1
2
3
4
Weight before the diet
180
125
240
150
Weight after six weeks
170
130

215
152
For the population of all adults, assume that the weight loss
after six weeks on the diet (weight before beginning the diet
minus weight after six weeks on the diet) is Normally
distributed with mean μ.
Reference: Ref 18-5
A 95% confidence interval for μ based on these data is
A.
7 ± 21.70.
B.
7 ± 13.64.
C.
7 ± 6.82.
D.
7 ± 4.00.
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
81.
Each person in a random sample of 2000 “likely voters” (as
defined by a professional polling organization) was questioned
about his or her political views. Of those surveyed, 1308 felt
that “the economy's state” was the most urgent national
concern.
Reference: Ref 20-1

Using the plus four estimate,, we estimate the proportion of
likely voters that felt the economy's state was the most urgent
national concern to be
A.
0.357.
B.
0.500.
C.
0.654.
D.
0.732.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
82.
A TV news program conducts a call-in poll about a proposed
city ban on smoking in public places. Of the 2467 callers, 1900
were opposed to the ban. Which of the following statements are
true with respect to using this sample to estimate p, the
proportion of all TV news viewers that favor such a ban on
smoking in public places?
A.
There is no way this sample can be viewed as an SRS of all TV
news viewers, so we can't use this sample to estimate p.
B.
The population is much larger than the sample, so it's okay to
use this sample to estimate p.
C.

n is so large that both the count of successes, and the count of
failures, are 10 or more, so it's okay to use this sample to
estimate p.
D.
There appear to be no violations to any of the assumptions made
in using the methods of this chapter. We should now be able to
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
83.
The American Veterinary Medical Association conducted a
survey of veterinary clinics to estimate the proportion that do
not treat large animals (cows, horses, etc.). The survey was
mailed to a random sample of 120 veterinary clinics throughout
the country and of these, 88 responded that they do not treat
large animals.
Reference: Ref 20-2
The standard error SE of the sample proportion of clinics that
do not treat large animals, is
A.
0.02.
B.
0.03.
C.
0.04.
D.
0.05.

Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
84.
Do SAT coaching classes work? Do they help students to
improve their test scores? Four students were selected randomly
from all of the students that completed an SAT coaching class.
For each student, we recorded their first SAT score (before the
class) and their second SAT score (after the coaching class).
Student
1
2
3
4
First SAT score
920
830
960
910
Second SAT score
1010
800
1000
980

To analyze these data, we should use
A.
the one-sample t test.
B.
the matched pairs t test.
C.
the two-sample t test.
D.
Any of the above are valid. It just needs to be a t since σ is
unknown.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
85.
In 1965, about 44% of the U.S. adult population had never
smoked cigarettes. A national health survey of 1472 U.S. adults
(presumably selected randomly) during 2010 revealed that 677
had never smoked cigarettes.
Reference: Ref 20-5
A 99% confidence interval for the proportion of U.S. adults in
2006 that have never smoked is
A.
0.461 to 0.560.
B.
0.426 to 0.493.
C.

0.481 to 0.540.
D.
0.487 to 0.534.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
86.
A researcher has developed a new drug designed to reduce
blood pressure. In an experiment, 21 subjects were assigned
randomly to the treatment group, and received the new
experimental drug. The other 23 subjects were assigned to the
control group, and received a standard, well known treatment.
After a suitable period of time, the reduction in blood pressure
for each subject was recorded. A summary of these data is:
n
s
Treatment group (new drug):
21
23.48
8.01
Control group (old drug):
23
18.52
7.15

Reference: Ref 19-1
The researcher suspects that the new drug results in greater
average reduction in blood pressure than the old drug does.
Based on these data, the computed two-sample tstatistic is
A.
1.84.
B.
2.16.
C.
2.31.
D.
4.70.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
87.
n

s
21
23.48
8.01
23
18.52
7.15
Reference: Ref 19-1
If we had used the more accurate software approximation to the
degrees of freedom, we would have used which of the following
for the approximate number of degrees of freedom for the t-
procedures?
A.
37
B.
38
C.
40
D.
100
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:

C
88.
A sports writer wished to see if a football filled with helium
travels farther, on average, than a football filled with air. To
test this, the writer used 20 adult male volunteers. These
volunteers were randomly divided into two groups of 10
subjects each. Group 1 kicked a football filled with helium to
the recommended pressure. Group 2 kicked a football filled with
air to the recommended pressure. The mean yardage for group 1
was = 32 yards, with a standard deviation s1 = 9 yards. The
mean yardage for group 2 was = 27 yards, with a standard
deviation s2 = 6 yards. Assume the two groups of kicks are
independent. Let μ1 and μ2 represent the mean yardage we
would observe for the entire population represented by the
volunteers if all members of this population kicked,
respectively, a helium and an air-filled football. Assume that
two-sample t-procedures are safe to use.
Reference: Ref 19-2
Suppose the researcher had wished to test the hypotheses
H0: μ1 = μ2, Ha: μ1 > μ2.
The numerical value of the two-sample t statistic is
A.
0.36.
B.
1.46.
C.
2.57.
D.
4.08.
Correct

Points Earned:
1/1
Correct Answer:
B
Your Response:
B
89.
A sports writer wished to see if a football filled with helium
travels farther, on average, than a football filled with air. To
test this, the writer used 20 adult male volunteers. These
volunteers were randomly divided into two groups of 10
subjects each. Group 1 kicked a football filled with helium to
the recommended pressure. Group 2 kicked a football filled with
air to the recommended pressure. The mean yardage for group 1
was = 32 yards, with a standard deviation s1 = 9 yards. The
mean yardage for group 2 was = 27 yards, with a standard
deviation s2 = 6 yards. Assume the two groups of kicks are
independent. Let μ1 and μ2 represent the mean yardage we
would observe for the entire population represented by the
volunteers if all members of this population kicked,
respectively, a helium and an air-filled football. Assume that
two-sample t-procedures are safe to use.
Reference: Ref 19-2
Suppose the researcher had wished to test the hypotheses
H0: μ1 = μ2, Ha: μ1 > μ2.
The P-value for the test is (use the conservative Option 2 for the
degrees of freedom)
A.
larger than 0.10.
B.
C.

D.
below 0.01.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
90.
DDT is a pesticide banned in the United States for its danger to
humans and animals. In an experiment on the impact of DDT, 6
rats were exposed to DDT poisoning and 6 rats were not. For
each rat in the experiment, a measurement of nerve sensitivity
was recorded. The researchers suspected that the mean nerve
sensitivity for rats exposed to DDT is greater than that for rats
not poisoned. The data follow:
Poisoned rats:
12.207
16.869
25.050
22.429
8.456
20.589
Unpoisoned rats:
11.074
9.686
12.064
9.351
8.182
6.642
Let be the mean nerve sensitivity for rats poisoned with DDT.

Let be the mean nerve sensitivity for rats not poisoned with
DDT.
Reference: Ref 19-4
The numerical value of the t statistic is
A.
0.57.
B.
1.93.
C.
6.00.
D.
2.99.
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
91.
In the United States, there is a strong relationship between
smoking and education, with well-educated people less likely to
smoke. A study in France included a sample of 459 men who
were selected at random from men who had visited a health
center for a routine checkup. Education is classified into three
categories corresponding to the highest level of education and
smoking status is classified into four categories.
Smoking Status
Education
Nonsmoker
Former
Moderate

Heavy
Total
Primary school
56
54
41
36
187
Secondary school
37
43
27
32
139
University
53
28
36
16
133
Total
146
125
104
84
459
Reference: Ref 23-1
This is an rc table. The number c has value
A.
2.
B.
3.

C.
4.
D.
6.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
92.
Smoking Status
Education
Nonsmoker
Former
Moderate
Heavy
Total
Primary school
56
54
41
36
187
Secondary school

37
43
27
32
139
University
53
28
36
16
133
Total
146
125
104
84
459
Reference: Ref 23-1
The degrees of freedom for the chi-square test for this two-way
table are
A.
2.
B.
6.
C.
7.
D.
12.
Correct
Points Earned:
1/1

Correct Answer:
B
Your Response:
B
93.
Recent revenue shortfalls in a southern state led to a reduction
in the state budget for higher education. To offset the reduction,
the largest state university proposed a 20% tuition increase. It
was determined that such a large increase was needed to simply
compensate for lost support from the state. Random samples of
100 freshmen, 100 sophomores, 100 juniors, and 100 seniors
from the university were asked whether they were strongly
opposed to the increase, given that it was the minimum increase
necessary to maintain the university's budget at current levels.
The results are given in the following table.
Strongly opposed
Freshman
Sophomore
Junior
Senior
Yes
78
72
58
36
No
22
28
42
64
Reference: Ref 23-2
To compare the four classes (freshman, sophomore, junior,
senior) with respect to their opinion regarding the proposed

tuition increase (yes = opposed, no = not opposed), which
distribution should we calculate?
A.
the joint distribution of year in school and opinion
B.
the marginal distribution of year in school
C.
the conditional distribution of opinion given year in school
D.
the conditional distribution of year in school given opinion
Incorrect
Points Earned:
0/1
Correct Answer:
C
Your Response:
B
94.
Do women and men treat female and male children differently?
An observational study was conducted near the primate exhibit
at the Columbus Zoo on weekends in 1997. The data are from
39 groups of three—one adult female, one adult male, and one
toddler, in which the toddler was being carried. Recorded below
is which adult (male or female) was carrying the toddler by the
sex of the toddler.
Sex of toddler
Sex of adult carrying toddler
Male
Female
Male

8
17
Female
6
8
Reference: Ref 23-4
Suppose we wish to test the null hypothesis that the proportion
of male adults and the proportion of female adults carrying a
toddler is the same, regardless of the sex of the toddler. Under
the null hypothesis, the expected number of male adults who
would be carrying a female toddler according to the table is
A.
8.97.
B.
16.02.
C.
18.97.
D.
39.00.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
95.

sex of the toddler.
Sex of toddler
Male
Female
Male
8
17
Female
6
8
Reference: Ref 23-4
The numerical value of the chi-square statistic for testing
independence of sex of the adult and sex of the toddler is
A.
0.460.
B.
0.498.
C.
3.94.
D.
39.27.
Incorrect
Points Earned:
0/1
Correct Answer:

A
Your Response:
D
96.
To study the export activity of manufacturing firms in Korea,
questionnaires were mailed to an SRS of firms in each of three
industries that export many of their products. The response rate
was low, and to compare the industries it is important that the
response rates from the different industries be similar. Do the
data in the Minitab output shown in the following table provide
evidence of a difference in response rate between the four
industries?
The output includes the cell counts, the expected cell counts,
and the chi-square statistic. Expected counts are printed below
observed counts
Industry
Responded
Didn't respond
Total mailed
Machinery
33
94
127
34.67
92.33
Electrical equipment
21
79

100
27.30
72.70
Precision instruments
41
80
121
33.03
87.97
Chi-Sq = 4.754
Reference: Ref 23-5
This is an r c table. The number r has value
A.
1.
B.
2.
C.
3.
D.
4.
Correct
Points Earned:
1/1

Correct Answer:
C
Your Response:
C
97.
A study examines the personal goals of children in grades 4, 5,
and 6. A random sample of students was selected for each of the
grades 4, 5, and 6 from schools in Georgia. The students
received a questionnaire regarding achievement of personal
goals. They were asked what they would most like to do at
school: make good grades, be good at sports, or be popular.
Results are presented in the following table by the sex of the
child.
Boys
Girls
Make good grades
192
590
Be popular
64
90
Be good in sports
188
80
Reference: Ref 23-6
Which hypotheses are being tested by the chi-square test?
A.
The null hypothesis is that personal goals and sex are
independent, and the alternative is that they are dependent.
B.
The null hypothesis is that the mean personal goal is the same
for boys and girls, and the alternative is that the means differ.

C.
The distribution of personal goals is different for boys and
girls.
D.
The distribution of sex is different for the three different
personal goals.
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
98.
A study examines the personal goals of children in grades 4, 5,
and 6. A random sample of students was selected for each of the
grades 4, 5, and 6 from schools in Georgia. The students
received a questionnaire regarding achievement of personal
goals. They were asked what they would most like to do at
school: make good grades, be good at sports, or be popular.
Results are presented in the following table by the sex of the
child.
Boys
Girls
Make good grades
192
590
Be popular
64
90
Be good in sports
188
80

Reference: Ref 23-6
The data are going to be summarized by the researchers
computing the conditional distributions of personal goals for
boys and girls. For what proportion of girls is it most important
to make good grades?
A.
0.222
B.
0.432
C.
0.754
D.
0.776
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
99.
A candidate for one of Ohio's two U.S. Senate seats wishes to
compare her support among registered voters in the northern
half of the state with her support among registered voters in the
southern half of the state. A random sample of 2000 registered
voters in the northern half of the state is selected, of which
1062 support the candidate. Additionally, a random sample of
2000 registered voters in the southern half of the state is
selected, of which 900 support the candidate.
Reference: Ref 21-1

Using the large-sample estimate, we estimate that the proportion
of registered adults in the northern half of the state who support
this candidate is
A.
0.469.
B.
0.531.
C.
0.546.
D.
0.825.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
100.
In a large midwestern university (the class of entering freshmen
is 6000 or more students), an SRS of 100 entering freshmen in
1999 found that 20 finished in the bottom third of their high
school class. Admission standards at the university were
tightened in 1995. In 2001, an SRS of 100 entering freshmen
found that 10 finished in the bottom third of their high school
class. Let and be the proportion of all entering freshmen in
1999 and 2001, respectively, who graduated in the bottom third
of their high school class.
Is there evidence that the proportion of freshmen who graduated
in the bottom third of their high school class in 2001 has been
reduced, as a result of the tougher admission standards adopted
in 2000, compared to the proportion in 1999? To determine this,

you test the hypotheses
H0: p1 = p2, Ha: p1 > p2.
Reference: Ref 21-2
A 99% confidence interval for is
A.
0.050 to 0.150.
B.
0.017 to 0.183.
C.
0.002 to 0.198.
D.
–0.029 to 0.229.
Incorrect
Points Earned:
0/1
Correct Answer:
D
Your Response:
B
Top of Form
Bottom of Form
Continue
mulative Final Exam
Submitted by [email protected] on 7/12/2012 10:21:41 PM
Points Awarded
90
Points Missed
10

Percentage
90%
1.
The histogram below shows the time visitors to a museum spent
browsing an exhibit on a Saturday. There were 300 visitors that
day. The following histogram is of the data collected.
Reference: Ref 1-3
The percent of visitors spending more than 85 minutes at the
museum is closest to
A.
about 5%.
B.
about 20%.
C.
about 30%.
D.
over 40%.
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
2.
The following is a histogram showing the distribution of the
average property damage caused by tornadoes per year over the
period 1950 to 1999 in each of the 50 states and Puerto Rico.
The data are in millions of dollars and the class intervals are “0

to < 10,” “10 to < 20,” and so forth.
Reference: Ref 1-6
The percent of the data with average property damage of under
20 million dollars is about
A.
20%.
B.
30%.
C.
40%.
D.
60%.
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
3.
A violin student records the number of hours she spends
practicing during each of nine consecutive weeks.
6.2
5.0
4.3
7.4
5.8
7.2
8.4
1.2
6.3

Reference: Ref 2-1
What is the first quartile for this data?
A.
5.00 hours
B.
5.76 hours
C.
7.20 hours
D.
4.65 hours
Incorrect
Points Earned:
0/1
Correct Answer:
A
Your Response:
D
4.
A stemplot of ages of 18 faculty members in a college math
department follows. 4|3 represents 43 years.
Reference: Ref 2-2
The first quartile of the age of the faculty members at
Wilmington State is
A.
38 years.
B.
38.5 years.

C.
39 years.
D.
40 years.
Incorrect
Points Earned:
0/1
Correct Answer:
B
Your Response:
C
5.
The exam scores (out of 100 points) for all students taking an
introductory Statistics course are used to construct the
following boxplot.
Reference: Ref 2-3
Based on this boxplot, the interquartile range is closest to
A.
10.
B.
25.
C.
50.
D.
80.
Correct
Points Earned:
1/1

Correct Answer:
B
Your Response:
B
6.
During the early part of the 1994 baseball season, many sports
fans and baseball players noticed that the number of home runs
seemed to be unusually large. Below are the team-by-team
statistics on home runs hit from opening day through June 3 of
the 1994 season. They are given as separate stemplots for the
number of home runs by American and National League teams.
Reference: Ref 2-4
Which of the following is a correct statement?
A.
The American League plot is reasonably symmetric.
B.
The National League plot is slightly skewed to the left.
C.
The median number of home runs hit by American League teams
was higher than by National League teams.
D.
All of the above
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
7.

A sample was taken of the salaries of 20 employees of a large
company. The following is a boxplot of the salaries (in
thousands of dollars) for this year.
Reference: Ref 2-5
Based on this boxplot, which of the following statements is
true?
A.
The interquartile range is about $20,000.
B.
The minimum salary is $20,000.
C.
The range of the salaries is about $75,000.
D.
The median salary is about $40,000.
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
8.
The five-number summary of a set of data
A.
is the mean, standard deviation, first quartile, median, and third
quartile.
B.
is the mean, median, mode, variance, and standard deviation.
C.
can be computed from the information in a stemplot.

D.
is the minimum, the interquartile range, the mean, the median,
and the maximum.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
9.
The histogram below shows the average property damage in
millions of dollars caused by tornadoes over a 50-year period in
each of the states and Puerto Rico.
Reference: Ref 2-6
From the histogram, the first quartile must be
A.
B.
C.
D.
greater than 10.
Correct
Points Earned:
1/1
Correct Answer:

A
Your Response:
A
10.
The average salary of all female workers at a large plant is
$35,000. The average salary of all male workers at the plant is
$41,000. If there are more female workers than female workers
at the plant, then the average salary at the plant must be
A.
exactly $38,000.
B.
C.
smaller than $38,000.
D.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
11.
The volume of oxygen consumed (in liters per minute) while a
person is at rest and while he or she is exercising (running on a
treadmill) was measured for each of 50 subjects. The goal is to
determine if the volume of oxygen consumed during aerobic
exercise can be estimated from the amount consumed at rest.
The results are plotted below.
Reference: Ref 4-1

The scatterplot suggests
A.
there is a positive association between the volume of oxygen
consumed at rest and while running.
B.
there is an outlier in the plot.
C.
Both a and b
D.
Neither a nor b
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
12.
A researcher states that bone density in women is negatively
associated with age. This means that
A.
above-average values of age tend to accompany below-average
values of bone density.
B.
above-average values of age tend to accompany above-average
C.
below-average values of age tend to accompany below-average
D.
older women aren't any more likely than younger women to

have below-average bone density.
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
13.
The form of the relationship in the following scatterplot might
best be described as
A.
negative and linear.
B.
curved.
C.
extrapolated.
D.
clustered.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
14.
Which of the following statements is true?
A.

The correlation coefficient equals the proportion of times two
variables lie on a straight line.
B.
The correlation coefficient will be +1.0 only if all the data lie
on a perfectly horizontal straight line.
C.
The correlation coefficient measures the fraction of outliers that
appear in a scatterplot.
D.
The correlation coefficient is a unitless number and must always
lie between –1.0 and +1.0, inclusive.
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
15.
The data in the scatterplot below are from a small data set.
The data were classified as either being collected in the winter
or in the summer. Those collected in the winter are indicated by
open circles and those in the summer by solid circles. The
overall correlation of the data in this scatterplot is
A.
positive.
B.
negative since the open circles display a negative trend and the
solid circles display a negative trend.
C.
near 0 since the open circles display a negative trend and the

solid circles display a negative trend, but the trend from the
open circles to the solid circles is positive. The different trends
cancel.
D.
impossible to compute for such a data set.
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
16.
A locomotive's “adhesion” is the locomotive's pulling force as a
multiple of its weight. This is an important performance
measure of a locomotive. A diesel locomotive model has
adhesion that varies in actual use according to a Normal
distribution with mean 0.37 and standard deviation 0.04.
Reference: Ref 3-3
The first quartile for the adhesion distribution is
A.
0.04.
B.
0.25.
C.
0.29 hours.
D.
0.34 hours.
Correct
Points Earned:

1/1
Correct Answer:
D
Your Response:
D
17.
The scores on the Wechsler Adult Intelligence Scale are
approximately Normal with μ = 100 and σ = 15.
Reference: Ref 3-5
The proportion of adults with scores between 80 and 120 is
closest to
A.
0.50.
B.
0.66.
C.
0.82.
D.
0.99.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
18.
The scores on the Wechsler Adult Intelligence Scale are
approximately Normal with μ = 100 and σ = 15.
Reference: Ref 3-5
The score needed to be among the highest 10% of all scores is

closest to
A.
81.
B.
119.
C.
75.
D.
125.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
19.
A company produces packets of soap powder labeled “Giant
Size 32 Ounces.” The actual weight of soap powder in such a
box has a Normal distribution with a mean of 33 oz and a
standard deviation of 0.7 oz. To avoid having dissatisfied
customers, the company says a box of soap is considered
underweight if it weighs less than 32 oz. To avoid losing
money, it labels the top 5% (the heaviest 5%) overweight.
Reference: Ref 3-6
How heavy does a box have to be for it to be labeled
overweight?
A.
31.60 oz
B.
31.85 oz

C.
34.15 oz
D.
34.40 oz
Incorrect
Points Earned:
0/1
Correct Answer:
A
Your Response:
C
20.
A market research company employs a large number of typists
to enter data into a computer database. The time taken for new
typists to learn the computer system is known to have a Normal
distribution with a mean of 130 minutes and a standard
deviation of 20 minutes. A candidate is automatically hired if he
or she learns the computer system in less than 100 minutes. A
cut-off time is set at the slowest 40% of the learning
distribution. Anyone slower than this cut-off time is not hired.
Reference: Ref 3-7
What proportion of candidates will be automatically hired?
A.
0.023
B.
0.067
C.
0.159
D.
0.309
Correct

Points Earned:
1/1
Correct Answer:
B
Your Response:
B
21.
In a study, nine tires of a particular brand were driven on a
track under identical conditions. Each tire was driven a
particular controlled distance (measured in thousands of miles),
and afterward the tread depth was measured. Tread depth is
measured in “mils.” Here, 1 mil is 0.001 inch. The least-squares
regression line was computed, and added to a scatterplot of
these data. On the plot, one data point is marked with an “X”.
The equation of the least-squares regression line is:
Tread Depth = 360.64 – 11.39x (thousands of miles)
Also, r2 = 0.953.
Reference: Ref 5-1
We might feel comfortable using the least-squares regression
equation to predict tread depth for a tire driven
A.
roughly between 0 and 30 thousand miles.
B.
roughly between 0 and 50 thousand miles.
C.
more than 50 thousand miles.
D.
cannot be determined from the information provided.

Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
22.
Also, r2 = 0.953.
Reference: Ref 5-1
Which of the following statements is true?
A.
About 95.3% of the variation in tread depth is explained by the
regression on miles.
B.
According to the least-squares regression line, the groove depth
of a new tire (driven 0 miles) is predicted to be 360.64 mils.
C.
According to the least-squares regression line, we would predict
a decrease in groove depth of 11.39 mils for each 1000 miles

driven on a tire.
D.
All of the above
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
23.
Also, r2 = 0.953.
Reference: Ref 5-1
Which of the following is true?
A.
The correlation between tread Depth and miles is –0.976.
B.
95.3% of the data points fall on the least-squares regression
line.

C.
The correlation between tread depth and miles is 0.976.
D.
The data value closest to the asterisk (*) is highly influential.
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
24.
A researcher wants to determine whether the rate of water flow
(in liters per second) over an experimental soil bed can be used
to predict the amount of soil washed away (in kilograms). The
researcher measures the amount of soil washed away for various
flow rates, and from these data calculates the least-squares
regression line to be
amount of eroded soil = 0.4 + 1.3 × (flow rate)
The correlation between amount of eroded soil and flow rate
would be
A.
1/1.3.
B.
1.3.
C.
positive, but we cannot say what the exact value is.
D.
either positive or negative. It is impossible to say anything
about the correlation from the information given.

Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
25.
Suppose we fit the least-squares regression line to a set of data.
Points with unusually large values of the residuals are called
A.
response variables.
B.
the slope.
C.
outliers.
D.
correlated.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
26.
John's parents recorded his height at various ages up to 66
months. Below is a record of the results.
Age (months)
36
48
54

60
66
Height (inches)
34
38
41
43
45
John's parents decide to use the least-squares regression line of
John's height on age based on the data in the previous problem
to predict his height at age 21 years (252 months). We conclude
A.
John's height, in inches, should be about half his age, in
months.
B.
The parents will get a fairly accurate estimate of his height at
age 21 years because the data are clearly correlated.
C.
such a prediction could be misleading because it involves
extrapolation.
D.
All of the above
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
27.
A study of elementary school children, ages 6 to 11, finds a
high positive correlation between shoe size x and score y on a

test of reading comprehension. The observed correlation is most
likely due to
A.
the effect of a lurking variable, such as age.
B.
a mistake, because the correlation must be negative.
C.
cause and effect (larger shoe size causes higher reading
comprehension).
D.
“reverse” cause and effect (higher reading comprehension
causes larger shoe size).
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
28.
According to the 2010 census, those states with an above
average number X of people who fail to complete high school
tend to have an above average number Y of infant deaths. In
other words, there is a positive association between X and Y.
The most plausible explanation for this association is
A.
X causes Y. Thus, programs to keep teens in school will help
reduce the number of infant deaths.
B.
Y causes X. Thus, programs that reduce infant deaths will
ultimately reduce the number of high school dropouts.
C.

lurking variables are probably present. For example, states with
large populations will have both a larger number of people who
fail to complete high school and a larger number of infant
deaths.
D.
the association between X and Y is purely coincidental. It is
implausible to believe the observed association could be
anything other than accidental.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
29.
The following table describes the opinions of 570 people.
Students were classified by class (freshman, sophomore, junior,
or senior), and by their opinion of campus residence quality
(high quality, medium quality, low quality).
Class
High
Medium
Low
Total
Freshman
65
25
20
110
Sophomore

55
30
45
130
Junior
60
40
70
170
Senior
30
60
70
160
Total
210
155
205
570
Reference: Ref 6-2
What percent of all students that responded are sophomores?
A.
25%
B.
19.3%

C.
22.8%
D.
29.8%
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
30.
If X and Y are categorical variables, thebest way to determine if
there is a relation between them is to
A.
calculate the correlation between X and Y.
B.
draw a scatterplot of the X and Y values.
C.
make a two-way table of the X and Y values.
D.
All of the above
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
31.

Reference: Ref 9-2
The names of the eight subjects follow.
1. Franklin
2. James
3. Wright
4. Edwards
5. Rust
6. Walsh
7. Gofberg
8. Williams
Use the following list of random digits: 41842 81868 71035
09001 43367 49497.
Start at the beginning of this list and use single-digit labels to
assign the first four subjects selected to have the steady price
group, and the remaining four to the fluctuating price group.
The subjects assigned to the fluctuating price group are
A.
Franklin, James, Wright, and Edwards.
B.

Edwards, Franklin, Williams, and James.
C.
Rust, Walsh, Gofberg, and Williams.
D.
James, Rust, Walsh, and Gofberg.
Incorrect
Points Earned:
0/1
Correct Answer:
D
Your Response:
B
32.
Reference: Ref 9-2
The experimental units are
A.
all business students at the college.
B.
the eight business students who participated.
C.
the business students who were in the fluctuating price group.
D.
Correct

Points Earned:
1/1
Correct Answer:
B
Your Response:
B
33.
In a study of human development, investigators showed two
movies that were different types to groups of children. Crackers
were available in a bowl, and the investigators compared the
number of crackers eaten by children watching both movies.
One movie was shown at 8 AM (right after the children had
breakfast) and the other at 11 AM (right before the children had
lunch). It was found that during the movie shown at 11 AM,
more crackers were eaten than during the movie shown at 8 AM.
The investigators concluded that the different types of movies
had different effects on appetite.
Reference: Ref 9-3
The treatment in this experiment is
A.
the number of crackers eaten.
B.
the different kinds of movies.
C.
the time each movie was shown.
D.
the bowls.
Correct
Points Earned:
1/1
Correct Answer:

B
Your Response:
B
34.
A study attempts to compare two sunscreens. Each of 50
subjects with varying skin complexions will use both sunscreens
— Screen A on one side of his or her body and Screen B on the
other side. For each subject, a coin is tossed in order to
determine which side receives Screen A and which receives
Screen B. Researchers measure the amount of ultraviolet light
exposure over both treated areas for each subject. This is an
example of
A.
a matched pairs experiment.
B.
a double-blind observational study.
C.
a stratified analysis.
D.
the placebo effect.
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
35.
Will a fluoride mouthwash used after brushing reduce cavities?
Twenty sets of twins were used to investigate this question. One
member of each set of twins used the mouthwash after each
brushing, the other did not. After six months, the difference in
the number of cavities of those using the mouthwash was

compared with the number of those who did not use the
mouthwash. This experiment uses
A.
random placeboes.
B.
double-blinding.
C.
double replication.
D.
a matched pairs design.
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
36.
A small math department has 6 faculty members and 30
students. It can send 6 people to a national convention and they
would like to send 4 students and 2 faculty members. Of the 30
students, 4 are selected randomly, and then 2 faculty members
are randomly selected from the six. This is an example of
A.
simple random sampling.
B.
stratified random sampling.
C.
voluntary response sampling.
D.
a census.

Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
37.
The Excite Poll is an online poll at poll.excite.com. You click
on an answer to become part of the sample. One poll question
was “Do you refer watching first-run movies at a movie theater,
or waiting until they are available on home video or pay-per-
view?” A total of 8896 people responded with 1118 saying they
preferred theaters. From this survey you can conclude that
A.
Americans prefer watching movies at home.
B.
a larger sample is necessary.
C.
the poll uses voluntary response, so the results tell us little
about the population of all adults.
D.
movie theaters should lower their prices.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
38.
At a large university a simple random sample of 5 female

professors is selected and a simple random sample of 10 male
professors is selected. The two samples are combined to give an
overall sample of 15 professors. The overall sample is
A.
a simple random sample.
B.
biased due to imbalance.
C.
a stratified sample.
D.
all of the above.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
39.
A simple random sample of 1200 adult Americans is selected,
and each person is asked the following question.
“In light of the huge national deficit, should the government at
this time spend additional money to establish a national system
of health insurance?"
Only 39% of those responding answered “Yes.” This survey
A.
is reasonably accurate since it used a large, simple random
sample.
B.
probably overstates the percentage of people that favor a system

of national health insurance.
C.
probably understates the percentage of people that favor a
system of national health insurance.
D.
is very inaccurate, but neither understates nor overstates the
percentage of people that favor a system of national health
insurance. Since simple random sampling was used, it is
unbiased.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
40.
A 1992 Roper poll found that 22% of Americans say that the
Holocaust may not have happened. The actual question asked in
the poll was
“Does it seem possible or impossible to you that the Nazi
extermination of the Jews never happened?"
and 22% responded “Possible.” The results of this poll cannot
be trusted because
A.
undercoverage is present. Obviously, those people who did not
survive the Holocaust could not be in the poll.
B.
the question is worded in a confusing manner.
C.
we do not know who conducted the poll or who paid for the

results.
D.
nonresponse is present. Many people will refuse to participate,
and those that do will be biased in their opinions.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
41.
In a survey of sleeping habits, 8400 national adults were
selected randomly and contacted by telephone. Respondents
were asked, “Typically, how many times per week do you sleep
less than 6 hours during the night?” On average, those surveyed
reported an average of 1.8 nights per week in which they got
less than 6 hours of sleep.
Reference: Ref 11-1
Which of the following is true with respect to this scenario?
A.
8400 is the size of the population being studied.
B.
1.8 is a statistic and represents an estimate of the unknown
value of a parameter of interest.
C.
1.8 is a parameter and represents an estimate of the unknown
value of a statistic of interest.
D.
None of the above
Correct

Points Earned:
1/1
Correct Answer:
B
Your Response:
B
42.
The variability of a statistic is described by
A.
the spread of its sampling distribution.
B.
the amount of bias present.
C.
the vagueness in the wording of the question used to collect the
sample data.
D.
the stability of the population it describes.
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
43.
Parts being manufactured at a plant are supposed to weigh 40
grams. Suppose the distribution of weights has a Normal
distribution with mean 40 grams and standard deviation 2
grams. Quality control inspectors randomly select 16 parts,
weigh each, and then compute the sample average weight for the
16 parts.
Reference: Ref 11-7

The sampling distribution of the sample mean
A.
is exactly Normal with mean 40 grams and standard deviation
0.5 grams.
B.
is approximately Normal with mean 40 grams and standard
deviation 0.5 grams.
C.
is meaningless in this problem, since only one sample is being
selected.
D.
cannot be determined since the sample size (16) is fairly small.
Incorrect
Points Earned:
0/1
Correct Answer:
A
Your Response:
B
44.
selected.
Reference: Ref 11-8
How many bags should be selected so that the standard
deviation of the sample mean is 0.1 ounces?
A.
8 bags

B.
10 bags
C.
64 bags
D.
100 bags
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
45.
A North American roulette wheel has 38 slots, of which 18 are
red, 18 are black, and 2 are green.
Reference: Ref 10-1
Suppose you decide to bet on red on each of 10 consecutive
spins of the roulette wheel. Suppose you lose all 5 of the first
wagers. Which of the following is true?
A.
You should get more spins of red on the next 5 spins of the
wheel, since we didn't get any on the first 5 spins.
B.
The wheel is not working properly. It favors outcomes that are
not red. Hence, during the next five spins of the wheel, we're
likely to continue to see few red outcomes.
C.
We're due for a win, so the sixth spin of the wheel is very likely
to come up red.
D.
What happened on the first 5 spins tells us nothing about what

will happen on the next 5 spins.
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
46.
An assignment of probabilities to events in a sample space must
obey which of the following?
A.
The probability of any event must be a number between 0 and 1,
inclusive.
B.
They must sum to 1 when adding over all events in the sample
space.
C.
They must obey the addition rule for disjoint events.
D.
All of the above
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
47.
Event A occurs with probability 0.2. Event B occurs with
probability 0.3. Event C occurs with probability 0.4. If A, B,

and C are disjoint, then
A.
P(A or B) = 0.5.
B.
P(A or C) = 0.6.
C.
P(A or B or C) = 0.9.
D.
All of the above
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
48.
At a small college, all entering freshmen must take a foreign
language class, chosen from the languages Spanish, French,
Swahili, Chinese, and Arabic. The probability distribution for
the language studied by a randomly selected freshman is
summarized in the following table:
Blood Type
Spanish
French
Swahili
Chinese
Arabic
Probability
?
0.12
0.09
0.19

0.12
Reference: Ref 10-4
The probability that the freshman is studying Chinese or
Swahili is
A.
0.28.
B.
0.31.
C.
0.72.
D.
1.00.
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
49.
I choose a card at random from a well-shuffled deck of 52
cards. There is a 1/4 probability that the card chosen is a spade,
a 1/4 probability that the card is a heart, a 1/4 probability that
the card is a diamond, and a 1/4 probability that the card is a
club. Both spades and clubs are black cards, while hearts and
diamonds are red.
Reference: Ref 10-5
The probability that the card chosen is not a spade is
A.

0.25.
B.
0.50.
C.
0.75.
D.
1.00.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
50.
The density curve for a continuous random variable X has which
of the following properties?
A.
The probability of any event is the area under the density curve
and above the values of X that make up the event.
B.
The total area under the density curve for X must be exactly 1.
C.
The probability of any event of the form X = constant is 0.
D.
All of the above
Correct
Points Earned:
1/1
Correct Answer:
D

Your Response:
D
51.
A deck of cards is shuffled, and you choose one at random,
observe its color, and replace it in the set. The cards are
thoroughly reshuffled, and you again choose a card at random,
observe its color, and replace it in the set. This process is
repeated until you get a red card with X denoting the number of
draws required. The random variable X has which of the
following probability distributions?
A.
the Normal distribution, with mean 26 and variance 13
B.
the binomial distribution, with parameters n = 52 and p = 0.5
C.
the binomial distribution, with parameters n = 26 and p = 0.5
D.
None of the above
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
52.
In an instant lottery, your chances of winning are 0.1. If you
play the lottery five times and outcomes are independent, the
probability that you lose all five times is
A.
0.900.
B.

0.590.
C.
0.410.
D.
0.100.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
53.
A local politician claims that 1 in 5 automobile accidents
involves a teenage driver. He is advocating increasing the age at
which teenagers can drive alone. Over a 2-month period there
are 67 accidents in your city, and only 9 of them involved a
teenage driver. If the politician is correct, what is the chance
that you would observe 9 or fewer accidents involving a teenage
driver?
A.
0.0524
B.
0.0901
C.
0.1343
D.
0.200
Correct
Points Earned:
1/1

Correct Answer:
B
Your Response:
B
54.
A roulette wheel has 38 slots in which the ball can land. Two of
the slots are green, 18 are red, and 18 are black. The ball is
equally likely to land in any slot. The roulette wheel is going to
be spun twice and the outcomes of the two spins are
independent.
Reference: Ref 12-1
The probability that it lands on red at least once is
A.
0.4986.
B.
0.7230.
C.
0.7756.
D.
0.9474.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
55.
A survey of college students finds that 20% like country music,
15% like gospel music, and 10% like both country music and
gospel music.
Reference: Ref 12-2

The proportion of students that like neither country music nor
gospel music is
A.
25%.
B.
40%.
C.
75%.
D.
90%.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
56.
A system has two components that operate in parallel, as shown
in the following diagram. Because the components operate in
parallel, at least one of the components must function properly
if the system is to function properly. The probabilities
of failures for the components 1 and 2 during one period of
operation are 0.20 and 0.03, respectively. LetF denote the event
that component 1 fails during one period of operation
and G denote the event that component 2 fails during one period
of operation. The component failures are independent.
Reference: Ref 12-3
The probability that the system functions properly during one
period of operation is closest to

A.
0.994.
B.
0.970.
C.
0.940.
D.
0.776.
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
57.
Female
Male
Total
15 to 17 years
89
61
150
18 to 24 years
5,668
4,697
10,365
25 to 34 years
1,904
1,589

3,493
35 years or older
1,660
970
2,630
Total
9,321
7,317
16,638
Reference: Ref 12-5
The probability that the selected student is a female that is 15 to
17 years old is
A.
0.005.
B.
0.010.
C.
0.560.
D.
0.593.
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
58.

Female
Male
Total
15 to 17 years
89
61
150
18 to 24 years
5,668
4,697
10,365
25 to 34 years
1,904
1,589
3,493
35 years or older
1,660
970
2,630
Total
9,321
7,317
16,638
Reference: Ref 12-5
Given that the selected student is female, the conditional
probability that he is 25 to 34 years old is
A.
0.545.
B.
0.204.
C.

0.114.
D.
0.008.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
59.
A stack of four cards contains two red cards and two black
cards. I select two cards, one at a time, and do not replace the
first card selected before selecting the second card. Consider
the events
A = the first card selected is red.
B = the second card selected is red.
The events A and B are
A.
independent.
B.
disjoint.
C.
conditionals.
D.
None of the above
Incorrect
Points Earned:
0/1

Correct Answer:
D
Your Response:
C
60.
In a particular game, a fair die is tossed. If the number of spots
showing is a six, you win $6, if the number of spots showing is
a five, you win $3, if the number of spots showing is 4, you win
$2, and if the number of spots showing is 3, you win $1. If the
number of spots showing is 1 or 2, you win nothing. You are
going to play the game twice.
Reference: Ref 12-6
The probability that you win something on each of the two plays
of the game is
A.
1/6.
B.
1/3.
C.
4/9.
D.
1/4.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
61.
A medical researcher treats 400 subjects with high cholesterol
with a new drug. The average decrease in cholesterol level is =

90 after two months of taking the drug. Assume that the
decrease in cholesterol after two months of taking the drug
follows a Normal distribution, with unknown mean μ and
standard deviation σ = 30.
Reference: Ref 14-1
A 95% confidence interval for μ is
A.
90 ± 1.96.
B.
90 ± 2.94.
C.
90 ± 3.92.
D.
90 ± 58.8.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
62.
Reference: Ref 14-2
A 99% confidence interval for μ is
A.
49.80 to 50.20.

B.
48.78 to 51.22.
C.
48.39 to 51.61.
D.
40.2 to 59.8.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
63.
Reference: Ref 14-2
Suppose I had measured the lifetimes of a random sample of
100 tires rather than 64. Which of the following statements is
true?
A.
increase.
B.
decrease.
C.
The margin of error for our 99% confidence interval would stay
the same since the level of confidence has not changed.
D.

σ would decrease.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
64.
To assess the accuracy of a laboratory scale, a standard weight
known to weigh 1 gram is repeatedly weighed a total of n times,
and the mean of the weighings is computed. Suppose the scale
readings are Normally distributed, with unknown mean m and
standard deviation σ = 0.01 g. How large should n be, so that a
95% confidence interval for mhas a margin of error of ±
0.0001?
A.
100
B.
196
C.
10,000
D.
38,416
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D

65.
H0: μ = 110, Ha: μ 110
Reference: Ref 15-1
If you observe a sample mean of = 115.35, what is the
corresponding P-value?
A.
0.058
B.
0.029
C.
0.787
D.
None of the above
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
66.

A university administrator obtains a sample of the academic
records of past and present scholarship athletes at the
university. The administrator reports that no significant
difference was found in the mean GPA (grade point average) for
male and female scholarship athletes (P = 0.287). This means
that
A.
the GPAs for male and female scholarship athletes are identical,
except for 28.7% of the athletes.
B.
the maximum difference in GPAs between male and female
scholarship athletes is 0.287.
C.
the chance of obtaining a difference in GPAs between male and
female scholarship athletes as large as that observed in the
sample if there is no difference in mean GPAs is 0.287.
D.
the chance that a pair of randomly chosen male and female
scholarship athletes would have a significant difference in
GPAs is 0.287.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
67.
Suppose we want a 90% confidence interval for the average
amount of time (in minutes) spent per week on homework by the
students in a large introductory statistics course at a large
university. The interval is to have a margin of error of 3
minutes, and the amount spent has a Normal distribution with a

standard deviation σ = 40 minutes. The number of observations
required is closest to
A.
22.
B.
482.
C.
683.
D.
1180.
Incorrect
Points Earned:
0/1
Correct Answer:
B
Your Response:
C
68.
Twenty-five seniors from a large metropolitan area school
district volunteer to allow their Math SAT test scores to be used
in a study. These 25 seniors had a mean Math SAT score of =
450. Suppose we know that the standard deviation of the
population of Math SAT scores for seniors in the district is σ =
100. Assuming the population of Math SAT scores for seniors in
the district is approximately Normally distributed, a 90%
confidence interval for the mean Math SAT score μ for the
population of seniors computed from these data is
A.
450 ± 32.9.
B.
450 ± 39.2.
C.

450 ± 164.5.
D.
not trustworthy.
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
69.
You conduct a statistical test of hypotheses and find that the
null hypothesis is statistically significant at level α = 0.05. You
may conclude that
A.
the test would also be significant at level α = 0.10.
B.
the test would also be significant at level α = 0.01.
C.
both a and b are true.
D.
neither a nor b is true.
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
70.
A certain population follows a Normal distribution, with

mean μ and standard deviation σ = 2.5. You collect data and test
the hypotheses
H0: μ = 1, Ha: μ 1
You obtain a P-value of 0.072. Which of the following is true?
A.
A 90% confidence interval for μ will exclude the value 1.
B.
A 90% confidence interval for μ will include the value 0.
C.
A 95% confidence interval for μ will exclude the value 1.
D.
A 95% confidence interval for μ will include the value 0.
Incorrect
Points Earned:
0/1
Correct Answer:
A
Your Response:
C
71.
A researcher wishes to determine if the use of an herbal extract
improves memory. Subjects will take the herbal extract
regularly during a 10-week period of time. After this course of
treatment, each subject has his or her memory tested using a
standard memory test. Suppose the scores on this test of
memory for all potential subjects taking the herbal extract
follow a Normal distribution with mean μ and standard
deviation σ = 6. Suppose also, that in the general population of
all people, scores on the memory test follow a Normal
distribution, with mean 50 and standard deviation σ = 4. The
researcher, therefore, decides to test the hypotheses
H0: μ = 50, Ha: μ > 50

To do so, the researcher has 100 subjects follow the protocol
described above. The mean score for these students is = 55.2
and the P-value is less than 0.0001.
Reference: Ref 16-1
It is appropriate to conclude which of the following?
A.
The researcher has conclusively proved that use of this herbal
extract improves memory.
B.
The researcher has strong evidence that people that use this
herbal extract, on average, have higher memory test scores than
those that don't use this extract. However, the difference may or
may not be important.
C.
The researcher has strong evidence that use of this herbal
supplement improves memory, and because the P-value is so
small, the difference must be substantial.
D.
None of the above
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
72.
A medical researcher is working on a new treatment for a
certain type of cancer. The average survival time after diagnosis
on the standard treatment is two years. In an early trial, she
tries the new treatment on three subjects who have an average

survival time after diagnosis of four years. Although the
survival time has doubled, the results are not statistically
significant even at the 0.10 significance level. The explanation
is
A.
the placebo effect is present, which limits statistical
significance.
B.
the sample size is small.
C.
that although the survival time has doubled, in reality the actual
increase is really two years.
D.
the calculation was in error. The researchers forgot to include
the sample size.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
73.
An SRS of 18 recent birth records at the local hospital was
selected. In the sample, the average birth weight was 119.6
ounces and the standard deviation was 6.5 ounces. Assume that
in the population of all babies born in this hospital, the birth
weights follow a Normal distribution, with mean μ.
Reference: Ref 18-1
We are interested in a 95% confidence interval for the
population mean birth weight. The margin of error associated
with the confidence interval is

A.
6.50 ounces.
B.
3.23 ounces.
C.
3.003 ounces.
D.
0.76 ounces.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
74.
The decrease in cholesterol level after eating a certain brand of
oatmeal for breakfast for one month in people with cholesterol
levels over 200 is Normally distributed, with mean (in
milligrams) μ and standard deviation σ = 3. The brand
advertises that eating its oatmeal for breakfast daily for one
month will produce a mean decrease in cholesterol of more than
10 points for people with cholesterol levels over 200, but you
believe that the mean decrease in cholesterol is actually less
than advertised. To explore this, you test the hypotheses
H0: μ = 10, Ha: μ < 10
and you obtain a P-value of 0.052. Which of the following is
true?
A.
At the α = 0.05 significance level, you have proved that H0 is
true.

B.
You have failed to obtain any evidence for Ha.
C.
There is some evidence against H0, and a study using a larger
sample size may be worthwhile.
D.
This should be viewed as a pilot study, and the data suggest that
further investigation of the hypotheses will not be fruitful at
the α = 0.05 significance level.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
75.
The height (in inches) of males in the United States is believed
to be Normally distributed, with mean μ. The average height of
a random sample of 50 American adult males is = 69.72 inches,
and the standard deviation of the 50 heights is s = 4.23. The
standard error of is
A.
0.084.
B.
0.357.
C.
0.598.
D.
0.731.
Correct

Points Earned:
1/1
Correct Answer:
C
Your Response:
C
76.
A radio show conducts a phone-in survey each morning.
Listeners are asked to call in with a response to the question of
the day. One morning in 2011, listeners were asked if they
supported or opposed term limits for members of Congress.
Remarkably, 88% of listeners that called in favored term limits.
We may safely conclude that
A.
there is overwhelming approval for Congressional term limits
among Americans generally.
B.
it is unlikely that if all Americans were asked their opinion, the
results would differ from that obtained in the poll.
C.
there is strong evidence that the majority of Americans believe
that there should be Congressional term limits.
D.
nothing, except that a great majority of those with strong
enough feelings on the issue to call in are in favor of
Congressional term limits. We cannot generalize any of this
survey's results to any larger population.
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:

D
77.
A special diet is intended to reduce systolic blood pressure. If
the diet is effective, the target is to have the average systolic
blood pressure of this group be below 150. After six months on
the diet, an SRS of 28 patients with high blood pressure had an
average cholesterol of = 143, with standard deviation s = 21. Is
this sufficient evidence that the diet is effective in meeting the
target? Assume the distribution of the cholesterol for patients in
this group is approximately Normal with mean μ.
Reference: Ref 18-2
Suppose the mean and standard deviation obtained were based
on a sample of 10 patients, rather than 28. The P-value would
be
A.
larger.
B.
smaller.
C.
unchanged, because the difference between and the
hypothesized value μ = 150 is unchanged.
D.
unchanged, because the variability measured by the standard
deviation stays the same.
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
78.

Which of the following will reduce the value of the power in a
statistical test of hypotheses?
A.
Decrease the type II error probability.
B.
Decrease the sample size.
C.
Reject the null hypothesis only if the P-value is smaller than the
level of significance.
D.
All of the above
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
79.
A researcher plans to conduct a test of hypotheses at the α =
0.10 significance level. She designs her study to have a power
of 0.70 at a particular alternative value of the parameter of
interest.
Reference: Ref 16-2
The probability that the researcher will commit a Type II error
for the particular alternative value of the parameter at which she
computed the power is
A.
0.10.
B.
0.30.

C.
0.70.
D.
equal to the 1 – (P-value) and cannot be determined until the
data have been collected.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
80.
You are thinking of employing a t-procedure to test hypotheses
about the mean of a population using a significance level of
0.05. You suspect the distribution of the population is not
Normal and may be moderately skewed. Which of the following
statements is correct?
A.
You should not use the t-procedure, because the population does
not have a normal distribution.
B.
You may use the t-procedure, provided your sample size is
large, say, at least 50.
C.
You may use the t-procedure, but you should probably claim the
significance level is only 0.10.
D.
You may not use the t-procedure, because t-procedures are
robust to non-Normality for confidence intervals but not for
tests of hypotheses.
Correct

Points Earned:
1/1
Correct Answer:
B
Your Response:
B
81.
A TV news program conducts a call-in poll about a proposed
city ban on smoking in public places. Of the 2467 callers, 1900
were opposed to the ban. Which of the following statements are
true with respect to using this sample to estimate p, the
proportion of all TV news viewers that favor such a ban on
smoking in public places?
A.
There is no way this sample can be viewed as an SRS of all TV
news viewers, so we can't use this sample to estimate p.
B.
The population is much larger than the sample, so it's okay to
C.
n is so large that both the count of successes, and the count of
failures, are 10 or more, so it's okay to use this sample to
estimate p.
D.
There appear to be no violations to any of the assumptions made
in using the methods of this chapter. We should now be able to
Incorrect
Points Earned:
0/1
Correct Answer:
A

Your Response:
C
82.
The American Veterinary Medical Association conducted a
survey of veterinary clinics to estimate the proportion that do
not treat large animals (cows, horses, etc.). The survey was
mailed to a random sample of 120 veterinary clinics throughout
the country and of these, 88 responded that they do not treat
large animals.
Reference: Ref 20-2
The standard error SE of the sample proportion of clinics that
do not treat large animals, is
A.
0.02.
B.
0.03.
C.
0.04.
D.
0.05.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
83.
A local board of education conducted a survey of residents in
the community concerning a property tax levy on the coming
local ballot. They randomly selected 850 residents in the
community and contacted them by telephone. Of the 850

residents surveyed, 410 supported the property tax levy.
Let p represent the proportion of residents in the community
that support the property tax levy.
Reference: Ref 20-3
A 90% confidence interval for p is
A.
0.4489 to 0.5159.
B.
0.4543 to 0.5105.
C.
0.4487 to 0.5161.
D.
0.4463 to 0.5185.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
84.
Reference: Ref 20-5
A 99% confidence interval for the proportion of U.S. adults in
2006 that have never smoked is
A.
0.461 to 0.560.

B.
0.426 to 0.493.
C.
0.481 to 0.540.
D.
0.487 to 0.534.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
85.
Reference: Ref 20-5
Suppose you wished to test whether there has been a change
since 1965 in the proportion of U.S. adults that have never
smoked cigarettes. You suspect that the proportion has grown
since 1965. Which of the following are the appropriate
hypotheses?
A.
H0: p = 0.44, Ha: p > 0.44
B.
H0: p = 0.51, Ha: p 0.51
C.
H0: p = 0.44, Ha: p 0.44
D.
H0: = 0.44, Ha: 0.44

Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
86.
n
s
21
23.48
8.01
23
18.52
7.15
Reference: Ref 19-1

The P-value for the test described in Question 5 (again, using
Option 2 for degrees of freedom) is
A.
larger than 0.05.
B.
C.
D.
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
87.
n
s

21
23.48
8.01
23
18.52
7.15
Reference: Ref 19-1
Which of the following would lead us to believe that the t-
procedures were not safe to use here?
A.
The two population distributions being studied are slightly non-
Normal.
B.
The sample medians and means for the two groups were slightly
different.
C.
The two population distributions are heavily skewed, and far
from Normal.
D.
Some subjects did not follow protocol, and these could be
outliers in the data.
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
88.

An inspector inspects large truckloads of potatoes to determine
the proportion p in the shipment with major defects prior to
using the potatoes to make potato chips. Unless there is clear
evidence that this proportion, p, is less than 0.10, he will reject
the shipment. He will test the hypotheses
H0: p = 0.10, Ha: p < 0.10.
He selects an SRS of 200 potatoes from the over 5000 potatoes
on the truck. Suppose that 12 of the potatoes sampled are found
to have major defects.
Reference: Ref 20-6
Using the plus four method, a 95% confidence interval for the
true proportion of potatoes in the truck that have major defects
is
A.
0.034 to 0.103.
B.
0.009 to 0.111.
C.
0.051 to 0.103.
D.
0.027 to 0.093.
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
89.
Is there a difference in the amount of airborne bacteria between
carpeted and uncarpeted rooms? In an experiment, 7 rooms were

carpeted and 7 were left uncarpeted. The rooms are similar in
size and function. After a suitable period of time, the
concentration of bacteria in the air was measured (in units of
bacteria per cubic foot) in all of these rooms. The data and
summaries are provided:
s
Carpeted rooms:
184
22.0
Uncarpeted rooms:
175
16.9
Reference: Ref 19-3
A 95% confidence interval for the difference in mean bacterial
concentration in the air of carpeted rooms versus uncarpeted
rooms is (use the conservative value for the degrees of freedom)
A.
–7.47 to 31.47.
B.
–11.55 to 29.55.
C.
–16.66 to 34.66.
D.
–18.89 to 42.89.
Correct
Points Earned:
1/1
Correct Answer:

C
Your Response:
C
90.
DDT is a pesticide banned in the United States for its danger to
humans and animals. In an experiment on the impact of DDT, 6
rats were exposed to DDT poisoning and 6 rats were not. For
each rat in the experiment, a measurement of nerve sensitivity
was recorded. The researchers suspected that the mean nerve
sensitivity for rats exposed to DDT is greater than that for rats
not poisoned. The data follow:
Poisoned rats:
12.207
16.869
25.050
22.429
8.456
20.589
Unpoisoned rats:
11.074
9.686
12.064
9.351
8.182
6.642
Let be the mean nerve sensitivity for rats poisoned with DDT.
Let be the mean nerve sensitivity for rats not poisoned with
DDT.
Reference: Ref 19-4
The numerical value of the standard error of the difference in
sample means is
A.
1.30.

B.
2.61.
C.
4.05.
D.
9.02.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
91.
Smoking Status
Education
Nonsmoker
Former
Moderate
Heavy
Total
Primary school
56
54
41
36

187
Secondary school
37
43
27
32
139
University
53
28
36
16
133
Total
146
125
104
84
459
Reference: Ref 23-1
Suppose we wish to test the null hypothesis that there is no
association between education level and smoking status. Under
the null hypothesis, the expected number of nonsmokers with a
primary school education is
A.
42.37.
B.
50.93.
C.
59.48.
D.
62.34.

Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
92.
Smoking Status
Education
Nonsmoker
Former
Moderate
Heavy
Total
Primary school
56
54
41
36
187
Secondary school
37
43
27
32
139

University
53
28
36
16
133
Total
146
125
104
84
459
Reference: Ref 23-1
The degrees of freedom for the chi-square test for this two-way
table are
A.
2.
B.
6.
C.
7.
D.
12.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
93.

Strongly opposed
Freshman
Sophomore
Junior
Senior
Yes
78
72
58
36
No
22
28
42
64
Reference: Ref 23-2
To compare the four classes (freshman, sophomore, junior,
senior) with respect to their opinion regarding the proposed
tuition increase (yes = opposed, no = not opposed), which
distribution should we calculate?
A.
the joint distribution of year in school and opinion

B.
the marginal distribution of year in school
C.
the conditional distribution of opinion given year in school
D.
the conditional distribution of year in school given opinion
Correct
Points Earned:
1/1
Correct Answer:
C
Your Response:
C
94.
Strongly opposed
Freshman
Sophomore
Junior
Senior
Yes
78
72
58

36
No
22
28
42
64
Reference: Ref 23-2
What is the contribution to the chi-square statistic from the cell
of strongly opposed juniors?
A.
0.1475
B.
0.1551
C.
3
D.
9
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
95.
A random sample of Ohio voters was asked about the number of
cars or trucks they own (one, two, or at least three) and the type
of community they lived in (rural, suburban, urban). The two-
way table follows.
Community Type

Number of cars
Rural
Suburban
Urban
One
120
230
530
Two
470
620
390
At least three
335
420
85
Reference: Ref 23-3
The proportion of rural residences with at least three cars or
trucks is
A.
0.105.
B.
0.303.
C.
0.362.
D.
0.399.
Correct
Points Earned:

1/1
Correct Answer:
C
Your Response:
C
96.
sex of the toddler.
Sex of toddler
Male
Female
Male
8
17
Female
6
8
Reference: Ref 23-4
The numerical value of the chi-square statistic for testing
independence of sex of the adult and sex of the toddler is
A.
0.460.
B.
0.498.

C.
3.94.
D.
39.27.
Correct
Points Earned:
1/1
Correct Answer:
A
Your Response:
A
97.
To study the export activity of manufacturing firms in Korea,
questionnaires were mailed to an SRS of firms in each of three
industries that export many of their products. The response rate
was low, and to compare the industries it is important that the
response rates from the different industries be similar. Do the
data in the Minitab output shown in the following table provide
evidence of a difference in response rate between the four
industries?
The output includes the cell counts, the expected cell counts,
and the chi-square statistic. Expected counts are printed below
observed counts
Industry
Responded
Didn't respond
Total mailed
Machinery
33
94
127

34.67
92.33
Electrical equipment
21
79
100
27.30
72.70
Precision instruments
41
80
121
33.03
87.97
Chi-Sq = 4.754
Reference: Ref 23-5
The P-value for testing the null hypothesis that the probability
of response is the same for the three industries against the
alternative that the probability is different for the three
industries

A.
is greater than 0.05.
B.
is between 0.025 and 0.05.
C.
is between 0.010 and 0.025.
D.
cannot be determined because these are not the hypotheses
being tested by the chi-square test.
Incorrect
Points Earned:
0/1
Correct Answer:
A
Your Response:
B
98.
A candidate for one of Ohio's two U.S. Senate seats wishes to
compare her support among registered voters in the northern
half of the state with her support among registered voters in the
southern half of the state. A random sample of 2000 registered
voters in the northern half of the state is selected, of which
1062 support the candidate. Additionally, a random sample of
2000 registered voters in the southern half of the state is
selected, of which 900 support the candidate.
Reference: Ref 21-1
Using the large-sample estimate, we estimate that the proportion
of registered adults in the northern half of the state who support
this candidate is
A.
0.469.
B.

0.531.
C.
0.546.
D.
0.825.
Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
99.
In a large midwestern university (the class of entering freshmen
is 6000 or more students), an SRS of 100 entering freshmen in
1999 found that 20 finished in the bottom third of their high
school class. Admission standards at the university were
tightened in 1995. In 2001, an SRS of 100 entering freshmen
found that 10 finished in the bottom third of their high school
class. Let and be the proportion of all entering freshmen in
1999 and 2001, respectively, who graduated in the bottom third
of their high school class.
Is there evidence that the proportion of freshmen who graduated
in the bottom third of their high school class in 2001 has been
reduced, as a result of the tougher admission standards adopted
in 2000, compared to the proportion in 1999? To determine this,
you test the hypotheses
H0: p1 = p2, Ha: p1 > p2.
Reference: Ref 21-2
A 99% confidence interval for is
A.

0.050 to 0.150.
B.
0.017 to 0.183.
C.
0.002 to 0.198.
D.
–0.029 to 0.229.
Correct
Points Earned:
1/1
Correct Answer:
D
Your Response:
D
100.
An SRS of 100 flights of a large airline (airline 1) showed that
64 were on time. An SRS of 100 flights of another large airline
(airline 2) showed that 80 were on time. Let p1 andp2 be the
proportion of all flights that are on time for these two airlines.
Reference: Ref 21-3
Is there evidence of a difference in the on-time rate for the two
airlines? To determine this, you test the hypotheses
H0: p1 = p2, Ha: p1 ≠ p2.
The P-value of your test of the hypotheses given is
A.
B.
C.
D.
below 0.001.

Correct
Points Earned:
1/1
Correct Answer:
B
Your Response:
B
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