Mathematics 8 Basic Concepts of Probability

8
Mathematics
Learner’s Module 11
Department of Education
Republic of the Philippines
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Mathematics – Grade 8
Learner’s Module
First Edition, 2013
ISBN: 978-971-9990-70-3
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Authors: Emmanuel P. Abuzo, Merden L. Bryant, Jem Boy B. Cabrella, Belen P.
Caldez, Melvin M. Callanta, Anastacia Proserfina l. Castro, Alicia R. Halabaso,
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iii
Table of Contents
Unit 4
Module 11: Introduction to Probability ....................................................555
Module Map....................................................................................................... 556
Pre-Assessment ................................................................................................ 557
Learning Goals .................................................................................................. 561
Lesson 1: Basic Concepts of Probability....................................................... 562
Activity 1 ........................................................................................................ 562
Activity 2 ........................................................................................................ 563
Activity 3 ........................................................................................................ 654
Activity 4 ........................................................................................................ 566
Activity 5 ........................................................................................................ 567
Activity 6 ........................................................................................................ 570
Activity 7 ........................................................................................................ 570
Activity 8 ........................................................................................................ 572
Activity 9 ........................................................................................................ 573
Activity 10 ...................................................................................................... 576
Activity 11 ...................................................................................................... 577
Activity 12 ...................................................................................................... 577
Activity 13 ...................................................................................................... 578
Activity 14 ...................................................................................................... 579
Activity 15 ...................................................................................................... 580
Activity 16 ...................................................................................................... 581
Activity 17 ...................................................................................................... 583
Summary/Synthesis/Generalization ............................................................... 585
Glossary of Terms ........................................................................................... 585
References and Website Links Used in this Module..................................... 586

I. INTRODUCTION AND FOCUS QUESTIONS
INTRODUCTION
TO PROBABILITY
How do you deal with these questions? Were you able to answer them with certainty?
In this module, you will learn more about the rich applications of the fundamental
counting principles and probability. Remember to search for the answer to the following
questions: How is the number of occurrences of an event determined? How does
knowledge of finding the likelihood of an event help you in your daily life?
II. LESSONS AND COVERAGE
In this module, you will examine the aforementioned questions when you study
the following lessons:
Lesson 1 – Basic Concepts of Probability
Lesson 2 – Probability of an Event: Experimental Probability and Theoretical Probability
Lesson 3 – Organizing Outcomes of an Event and the Fundamental Counting Principles
Lesson 4 – Problems Involving Probabilities of Events
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What are my chances of getting the
correct answer in a True/False-type
question? Multiple choice-type of
question?
Should I bring my umbrella
tomorrow?
Will I probably win in
this game?
How likely is it that I
will be called to recite
in our math class
today?
What are the possible
routes that I can take
in going to school?
Do you think it is possible for you to determine the chance of occurrence of an
event?
Have you at a certain time asked yourself the following questions?

556
In these lessons, you will learn to:
Lesson 1 Define experiment, outcomes, sample space, and event.
Lesson 2 Explain and interpret the probability of an event; and
Differentiate between an experimental probability and a theoretical
probability.
Lesson 3 Count the number of occurrences of an outcome in an experiment and
organize them using a table, tree diagram, systematic listing, and the
fundamental counting principles.
Lesson 4 Solve simple problems involving probabilities of events.
Module MapModule Map
Here is a simple map of the lessons that will be covered in this module.
Probability
Basic Concepts
Theoretical
Probability
Counting
Techniques
Problems Involving
Probability of Simple
Events
Experimental
Probability

557
III. PRE-ASSESSMENT
Find out how much you already know about this module. Write the letter that you
think best answers the question. Please answer all items. After taking this short test, you
will see your score. Take note of the items that you were not able to answer correctly
and find for the right answers as you go through this module.
1. Which of the following DOES NOT belong to the group?
a. Chance
b. Interpretation
c. Possibilities
d. Uncertainty
2. All the possible outcomes that can occur when a coin is tossed twice are listed in
the box. What is the probability of having a head?
a.
1
4

b. 1
2

c. 3
4

d. 1
3. The local weather forecaster said that there is a 20% chance of rain tomorrow.
What is the probability that it will not rain tomorrow?
a. 0.2 b. 0.8 c. 20 d. 80
4. A relative-frequency distribution for scores in a 5-item test is provided in the table
below.

Score 0 1 2 3 4 5
Relative
Frequency
0.105 0.316 0.352 0.180 0.043 0.004
Suppose that the passing score is 4, what is the probability that a randomly
selected student failed the quiz?
a. 0.047 b. 0.575 c. 0.773 d. 0.953
10
PISO
APOLINARIO
MABINI
ANDRES
BONIFACIO
HH TH
TT HT
2013

558
5. A spinner with three equal divisions was spinned 1 000 times. The following
information was recorded. What is the probability of the spinner
landing on RED?

Outcome Blue Red Yellow
Spins 448 267 285
a. 27% b. 29% c. 45% d. 73%
6. Suppose you toss two fair coins once, how many possible outcomes are there?
a. 1 b. 2 c. 4 d. 8
7. A balanced die is rolled. What is the probability of rolling a number that is not 3?
a. 0
6
or 0 b. 1
6
c. 5
6
d. 6
6
or 1
8. In a 500-ticket draw for an educational prize, Ana’s name was written on 41 tickets.
What is the probability that she would win?
a. 0.082 b. 0.122 c. 0.41 d. 0.82
9. Which of the following is TRUE?
a. Answering a true/false-type question has one possible outcome.
b. Flipping a coin thrice has 3 possible outcomes.
c. The probability of getting a head when a coin is tossed can be expressed
as 1
2
, 0.5 or 50%.
d. The probability of rolling 7 in a die is 1
7
.
10. The weather forecaster has announced that Region 1 has rainy (R), partly cloudy
(PR), and cloudy (C) weather. If the chance of having R is twice as the probability
of PR which is 2
7
, what is the correct table for probability?

a. c.
b. d.
11. A glass jar contains 40 red, green, blue, and yellow marbles. The probability of
drawing a single green marble at random is 1
5
. What does this mean?
Outcome R PR C
Probability 1
7
4
7
2
7
Outcome R PR C
Probability 1
7
2
7
4
7
Outcome R PR C
Probability 4
7
1
7
2
7
Outcome R PR C
Probability 4
7
2
7
1
7

559
a. There are 5 green marbles in the glass jar.
b. There are 8 green marbles in the glass jar.
c. There are more green marbles than the others.
d. There is only one green marble in the glass jar.
12. In a restaurant, you have a dinner choice of one main dish, one vegetable, and
one drink. The choices for main dish are pork and chicken meat. The vegetable
choices are broccoli and cabbage. The drink choices are juice and water. How
many choices are possible?
a. 8 b. 10 c. 12 d. 14
13. Arlene Joy got coins from her pocket which accidentally rolled on the floor. If there
were 8 possible outcomes, how many coins fell on the floor?
a. 3 b. 4 c. 8 d. 16
14. In a family of 3 children, what is the probability that the middle child is a boy?
a. 1
8
b. 1
4
c. 1
3
d. 1
2
15. Jun rolls two dice. The first die shows a 5. The second die rolls under his desk and
he cannot see it. Now, what is the probability that both dice show 5?
a. 1
36
b. 1
6
c. 9
36
d. 1
3
16. Mrs. Castro asked her students to do an activity.Afterwards, her students noticed that
the experimental probability of getting tails is 48%, while the mathematical/theoretical
probability is 50%. Being an attentive student, how would you explain this to your
classmates?
a. The experimental probability is wrong.
b. We should always rely on mathematical/theoretical probability.
c. It is normal for experimental probabilities to vary from the theoretical
probabilities but for a large number of trials, the two will be very close.
d. It is abnormal for the experimental probabilities to differ from the mathematical/
theoretical probabilities because the results must be the same.
17. You decided to order a pizza but you have to choose the type of crust and the
toppings. If there are only 6 possible combinations of ordering a pizza, from which
of the following should you choose from?
a. Crust: thin or deep dish
Topping: cheese or pepperoni
b. Crust: thin or deep dish
Topping: cheese, bacon or pepperoni

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c. Crust: thin or deep dish
Topping: cheese, bacon, sausage or pepperoni
d. Crust: thin or deep dish
Topping: cheese, bacon, sausage, pepperoni or hotdog
18. There are four teams in a basketball tournament. TeamAhas 25% chance of winning.
Team B has the same chance as Team D which has 5% more than team A. Team C
has half the chance of winning as team B. Which of the following has the correct table
of probabilities for winning the tournament?
a.
b.
c.
d.
19. You tossed a five-peso coin five times and you got heads each time. You tossed again
and still a head turned up. Do you think the coin is BIASED? Why?
a. I think the coin is biased because it favored the heads.
b. I think the coin is biased because it is expected to turn up tail for the next
experiments.
c. I think the coin is not biased because both faces of the coin have equal chances
of turning up.
d. I think the coin is not biased because the probability of turning heads up is 3
4
while that of tails is only 1
4
.
20. Your best friend asked you to accompany him to a carnival to play games of chances.
According to him, his horoscope states that he is so lucky that day and he wants to try
his luck at the carnival. How will you convince him not to go to the carnival?
a. I will ask him to review very well his notes on probability so that he can apply
them to a real-life situation like this.
b. Iwilltellhimthatwhatiswritteninthehoroscopeissometimestrueandsometimes
false so he would rather not go to the carnival.
Team A B C D
Probability
of winning
25% 30% 15% 30%
Team A B C D
Probability
of winning
25% 15% 15% 45%
Team A B C D
Probability
of winning
25% 15% 10% 50%
Team A B C D
Probability
of winning
25% 20% 20% 35%

561
c. I will give him instances wherein he could see the real picture of having a very
little chance of winning so that he will not be wasting his money and time.
d. I will convince him not to go to the carnival this time because we have to finish
first our project in Probability. Anyway, there will be other times to go and enjoy
all the games there.
LEARNING GOALS AND TARGETS:
• The learner demonstrates understanding of the basic concepts of probability.
• The learner is able to use precisely counting techniques and probability in solving
simple problems related to different fields of endeavour.

562
What to KnowWhat to Know
Begin this module by assessing what you have learned on the basic mathematical
concepts and your skills in performing the different mathematical operations which may
help you understand the lessons on Probability. As you go through this module, think
of the following essential questions: How is the number of occurrences of an event
determined? How does knowledge of finding the likelihood of an event help you in
your daily life? To find the answer, perform each activity to the best of what you can.
ANSWER ALL YOU CAN!
Activity 1
Relate each illustration below with your day-to-day activities. Fill in the blanks with the
correct words that would make the following sentences meaningful.
11 Basic Concepts
of ProbabilityLesson
EMILIO
AGUINALDO
EMILIO
AGUINALDO
Impossible Unlikely
1 in 6 Chance
4 in 5 Chance
Even Chance Likely Certain
1. Now is your ____________ to change for the better.
2. I’m ___________ that you can do better than what is expected of you.
3. Given the chance to win in the Math contest, I prefer the ____________.
4. You and I have ___________ chance to succeed in life.
2013
2013

563
BUDGET…, MATTERS!
Activity 2
Use the illustration below to answer the following questions correctly.
You just tried describing probability which is the possibility of occurrences of events
in a man’s life, which can be expressed as a fraction, a decimal, or a percent. As you move
on to the next activity, your prior knowledge on the basic concepts of probability and the
fundamental counting principles will be elicited.
QU
ESTIO
NS?
a. How did you come up with your answer?
b. How did you know that the words are appropriate for the given
phrases?
c. When do we use the word “less”? How about “more”?
d. When does less really become more?
e. How do you differentiate the meaning of “less” and “less than”?
How are these terms used in Mathematics?
QU
ESTIO
NS?
1. Are those words familiar to you?
2. What particular topic comes to your mind when you see the words in
the illustration?
3. What qualitative terms can be used to express probable occurrences
of events in life?
4. How else can the possible occurrence or likelihood of an event be
expressed?
5. Based on the illustration, how do you describe probability?
1. How many shirts are there? _____
2. How many pairs of short pants are there?_____
3. How many pairs of long pants are there?_____
4. How many different outfits can you choose? _____

564
Do the next activity to explore further on the basic concepts of probability and the
fundamental counting principles.
QU
ESTIO
NS?
1. How else can you find the number of possible outcomes?
2. Did you find difficulty in choosing which to wear? Why?
3. Aside from comfort, what do you consider when you choose an
outfit?
QU
ESTIO
NS
?
1. If you roll a die once, how many outcomes are possible? _______
2. What are those outcomes? _______
3. How do we call those outcomes? _______
4. Rolling two dice simultaneously, how many outcomes are
possible?_______
5. How did you find the answer? _______
LET’S ROLL IT!
Activity 3
Analyze the problem carefully. Fill in the table correctly and answer the questions
that follow.
You are holding a die. Your seatmate is holding another die. If both of you roll the
dice at the same time, how many outcomes are possible?
Sides of a
Die
1 2 3 4 5 6
1
2 3, 2 6, 2
3
4
5
6 5, 6

565
Life has a lot of uncertainties. Oftentimes, our decisions in life are done under
conditions of uncertainty. These are the probabilities of life.
What you will learn in the next section will also enable you to do the final project
which will involve you as a game analyst invited by the barangay officials to inform or
educate the community folks to be mindful of their chances of losing and winning in the
local carnivals so that they will not end up wasting too much of their time and money.
You will start by doing the next activities.
What to ProcessWhat to Process
Your goal in this section is to learn and understand the key concepts of probability
and the fundamental counting principle by conducting several experiments which would
lead you to differentiate experimental probability from theoretical probability.
As you move on, please be guided by the following questions: How is the number of
occurrences of an event determined? How does knowledge of finding the
likelihood of an event help you in your daily life?
The branch of mathematics that deals with uncertainly is the theory of probability.
Probability is a measure or estimation of how likely it is that an event will occur.
Activities such as tossing or flipping a coin or picking a card from a standard deck of
cards without looking which could be repeated over and over again and which have well-
defined results are called experiments. The results are called outcomes.
Illustration:
When you roll a balanced die once, there are 6 possible outcomes which are 1, 2, 3, 4,
5 or 6. “Getting an even number” includes 3 outcomes; these are ‘a 2’, ‘a 4’, and ‘a 6’. “Getting
an even number” is called an event.
The set of all possible outcomes of an experiment is the sample space or probability
space; and each individual outcome is a sample point.
Experiment Sample Space Sample Point
Flipping two coins HH, HT, TH, TT HH
Rolling a die 1, 2, 3, 4, 5, 6 5
Rolling a coin and a die
simultaneously
H1, H2, H3, H4, H5, H6
T1, T2, T3, T4, T5, T6
T3

566
(Group Activity)

Join Jayar and his friends perform the same experiment. Record
each outcome of your experiment. Then, fill in the blanks using the basic
concepts of probability to complete the paragraph.
Jayar and his friends decided to find the number of times three heads
“HHH” would come up when flipping three five-peso coins simultaneously. Every time Jayar
and his friends flip the fair coins is an ____________. The ____________ that they are look-
ing for is to come up with three heads: {HHH}. The ____________ is the set of all possible
outcomes: {HHH}, {HTH} … {TTT}.
These are the results of their experiment. Complete the table.
Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Trial 6 Trial 7 Trial 8 Trial 9
Coin 1 H H T T H H T T T
Coin 2 T T T H T H T H T
Coin 3 T H T H T H H T T
Outcome HTT HTH
Is it
{HHH}?
YES or NO
NO NO

In order to find all the ____________, they have to continue flipping the coins at least
30 times.
WORDS COME EASY!
Activity 4
EMILIO
AGUINALDO
EMILIO
AGUINALDO
EMILIO
AGUINALDO
2013
2013
Drawing a card from a deck
of 52 cards
13 Diamonds, 13 Hearts, 13
Spades, 13 Clubs (Ace, 2,
3, 4, 5, 6, 7, 8, 9, 10, Jack,
Queen, King)
Queen of Hearts
“Queen” is not a sample point because there are four Queens which are four different
sample points in a deck of cards.
Examples:
a. Getting a TTT when flipping a coin thrice
b. Choosing a “Queen” from a deck of cards (any of the 4 Queens)
c. Getting an “odd number” (1, 3, or 5) when rolling a die

567
QU
ESTIO
NS?
1. Were you able to complete the paragraph with the correct words?
2. Do the words come easy to you? Why?
3. After 9 trials, Jayar and his friends had 1 “HHH” event. Is the result of
the experiment close to what you have expected? What would have
they done to make it closer to what is expected?
4. In your group experiment, how many “HHH” events did you have? Is
the result of your experiment close to what is expected? Why?
5. What Jayar, his friends, and your group had performed uses
Experimental Probability. In your own understanding, how do you
define Experimental Probability?
WHAT IS THE PROBABILITY?
Activity 5
Probabilities can be solved theoretically in which each event is assumed to be equally
likely. Look carefully at the given set, then match column A with column B. Your answers will
help you understand the concept on the probability of an event.
Given: Set R = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12}
Column A Column B
The probability of having: a. 1
12
d. 6
12
or 1
2 _____ 1. a 10
_____ 2. a 13 b. 2
12
or 1
6
e. 6
12
or 1
12 _____ 3. odd numbers
_____ 4. even numbers c. 3
12
or 1
4
f. 0
12
or 0
_____ 5. an odd number divisible by 3
_____ 6. an even number divisible by 3
QU
ESTIO
NS
?
1. How many possible outcomes are there?
2. To have even numbers, how many favorable outcomes are there?
3. Considering your answers, how do you compute for the probability of
an event?
4. What formula can be used?
5. This activity uses Theoretical Probability. How do you define
Theoretical Probability?
To enrich your knowledge about the difference between Experimental Probability
and Theoretical Probability, you may visit these sites:
www.algebra-class.com/theoretical-probability.html
http://www.onlinemathlearning.com/theoretical-probability.html

568
Probability of Events

The probability of an event, P (event), is a number from 0 to 1 which tells how likely the
event is to happen.
Take a closer look at the probability line below.

Impossible Unlikely Even Chance Likely Certain

0

1
0 0.25 0.5 0.75 1
0% 25% 50% 75% 100%
Probability Rules
1. The probability of any event is a number (either a fraction, a decimal, or a percent)
from 0 to 1.
Examples: The weather forecast shows a 70% rain.
P (rain) = 70%
2. If an event will never happen, then its probability is 0.
Example: When a single die is rolled, find the probability of getting an 8.
Since the sample space consists of 1, 2, 3, 4, 5, and 6, it is impossible to get an 8.
Hence, P(8) = 0
6
= 0.
3. If an event is sure to happen, then the probability is 1.
Example: When a single die is rolled, what is the probability of getting a number
less than 7?
Since all the outcomes {1, 2, 3, 4, 5, 6} are less than 7,
P (number less than 7) = 6
6
= 1
4. The sum of the probabilities of all the outcomes in the sample space is 1.
Example:
In rolling a fair die, each outcome in the sample space has a probability of 1
6
.
Hence, the sum of the probabilities of the outcomes is 1.

If a fair coin is flipped, P(T) = 1
2
and P(H) = 1
2
If you flipped the coin ten times and got the following outcomes: H, H, H, T, H, T, T, H,
H, what is the probability that the last outcome will also be a Head (H)? How did you arrive at
your answer?
1
4
1
2
3
4

569
P (event) =
Number of favorable outcomes
Number of all possible outcomes
Examples:
1. What is the probability of getting a HEART from a deck of cards?
P (heart) = 13
52
= 1
4
2. There are 20 marbles in a container: 4 are red, 5 are blue and 11 are yellow. What
is the probability that a blue marble will be picked?
P (blue marble) = 5
20
= 1
4
Sometimes, getting an event affects the outcome of another event. Take a look at these
examples:
1. Five red candies are left in a bag of 40 different colored candies.
a. What is the probability that you will get a red candy?
How did you get your answer?
b. What are your chances of getting a red one when you pick again? Why?
How many candies are now in the bag?
How many red candies are there?
Getting the next candy without replacement is affected by the result of
the first attempt. Every time you get a piece of candy from a bag, the chance
of getting a red one will change. These are called dependent events.
2. Flipping a Coin
a. When you flip a coin, what is the probability of a
head landing up?
b. If you flip it again, what is the probability of getting a
tail?
The two events do not affect each other. They are
independent events.
1PISO
JOSE RIZAL
2013
red
red
red
red
red

570
LET’S TAKE AN ACTIVITY TOGETHER
Activity 6
SEE MY PROB-ABILITY!
Activity 7
(Group Activity)
Gather data on the number of typhoons that hit the country in the previous year. Using
the basic concepts of probability, come up with a report showing the estimated chances of a
typhoon hitting the country for each month.
The report should contain the following:
1. Representation of collected data.
2. Process of coming up with the estimated probabilities.
3. Explanation on what type of probabilities is generated in the task.
Rubric for the Written Group Report
4 3 2 1
Representation
of Data and
Explanation
Is complete,
organized,
and clear
Is complete and
organized
Is complete but
disorganized
Is incomplete
and
disorganized
Process/
Computation
Has correct and
appropriate
illustration or
solution
Has correct
illustration or
solution with
minor error
Has illustration
or
solution but has
errors
Has no
illustration
or solution
(Quiz)
Solve the following carefully, then write the correct answer on the space provided before
each number.
_____ 1. Earl Darenz is asked to choose a day from a week. What is the probability
of choosing a day which starts with S?
_____ 2. Choosing a month from a year, what is the probability of selecting a month
with 31 days?

571
_____ 3 . If a letter is chosen at random from the word PERSEVERANCE, what is the
probability that the letter chosen is E?
_____4. If one letter is chosen at random from the word TRUSTWORTHY, what is
the probability that the letter chosen is a consonant?
_____ 5. The sides of a cube are numbered 11 to 16. If Jan Renz rolled the cube
once, what is the probability of rolling a composite number?
_____ 6. A box contains 7 red balls, 5 orange balls, 4 yellow balls, 6 green balls, and
3 blue balls. What is the probability of drawing out an orange ball?
_____7. Of the 45 students in a class, 25 are boys. If a student is selected at random
for a field trip, what is the probability of selecting a girl?
_____ 8. Two fair coins are tossed simultaneously. What is the probability of showing
a tail (T) followed by a head (H)?
_____ 9. A spinner is divided equally and numbered as follows: 1, 1, 2, 3, 3, 4, 1, 1, 2,
4, 1, 2, 3, 4, 1, 2. What is the probability that the pointer will stop at an even
prime?
_____ 10. What is the probability of getting an 8 from a deck of 52 cards?
In the next activity, you will discover how useful the Fundamental Counting
Principle is. This principle is all about choices you can make given many possibilities.

572
COUNT AND ANSWER…
Activity 8
Read the following situations carefully then answer all the questions that may lead you
to understand the fundamental counting principle.
1. On a Saturday morning, you washed most of your clothes and they are still wet.
Your friend invites you to attend his birthday party and you are left with only 2 pants
and 3 shirts. In how many different ways can you dress? Make a tree diagram to
show all the choices you can make.
2. You go to a restaurant to buy some breakfast. The menu says, for food: pancakes,
waffles, or home fries; and for drinks: coffee, juice, hot chocolate, and tea. How
many different choices of food and drink do you have? Illustrate the choices by
using the table below.
Food/Drinks
Coffee
(C)
Juice
(J)
Hot chocolate
(H)
Tea
(T)
Pancake (P) PC PT
Waffles (W) WJ
Fries (F) FH
QU
ESTIO
NS
?
a. How many choices do you have for pants? _____________
b. How many choices for shirts are there? _____________
c. Draw a tree diagram to show the number of choices.
d. How many branches are there in the tree diagram? _____________
e. How are the branches of the tree diagram related to the number of
choices that you can make? Therefore, in how many different ways
can you dress? _____________
f. You have 2 choices for pants and 3 choices for shirts. What should
you do with the two tasks to get the answer easily and quickly?
______________

573
Should you want to have more examples on using the Fundamental Counting
Principle to determine the sample space, watch the video in this site:
http://www.algebra-class.com/fundamental-counting-principle.html
To have more practice on finding the total possible outcomes, please visit this site:
http://www.aaaknow.com/sta-basic-cntg.htm
QU
ESTIO
NS?
a. How many choices for food are there?
b. How many choices for drinks are there?
c. By counting, how many different choices of food and drink do you
have?
d. If the number of choices for food is f and d for drinks, what expression
helps you find the answer quickly and correctly?
You can get the total number of possible outcomes by using a tree diagram or a table;
however, it is time consuming. You can use the Fundamental Counting Principle to easily
find the total outcomes by multiplying the outcomes for each individual event. Thus, if you
have f ways to do the first event and s ways to do the second event, then you can find the total
number of outcomes by multiplying f and s, that is (f)(s).
AN INDIVIDUAL REPORT
Activity 9
Choose any of the given tasks.
a. In a local hospital or clinic, do a research to determine the number of child births
for each month last year.
b. In your school, determine the number of absentees in a class per month during the
previous school year.
Use the basic concepts of probability to come up with a report showing the number of
occurrences.
The report should contain the following:
a. Representation of collected data
b. Process of coming up with the estimated probabilities
c. Explanation on what type of probabilities is used in the task

574
Rubric for the Written Individual Report
4 3 2 1
Representation
of Data and
Explanation
It is complete,
organized
and clear
It is complete
and
organized
It is complete
but
disorganized
It is incomplete
and
disorganized
Process/
Computation
Has correct and
appropriate
illustration or
solution
Has correct
illustration or
solution with
minor errors
Has illustration
or
solution with
major errors
Has no
illustration
or solution
Great job! I’m certain you are ready to move on…
In this section, the discussion was about the basic concepts of probability, experimental
probability and theoretical probability, and the fundamental counting principles.
Go back to the previous section and compare your initial ideas with the discussion. How
much of your initial ideas are found in the discussion? Which ideas are different and need
revision?
Now that you know the important ideas about this topic, to the next section.

575
What I have learned so far...________________________
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________________
_________________________________________.
REFLECTIONREFLECTION

576
What to UnderstandWhat to Understand
Your goal in this section is to take a closer look at some aspects of the topic.
I’m certain that you are now ready to answer the different exercises to have a deeper
understanding of what you have learned. As you continue answering the next activities,
please search for the answer to the following questions:
How is the number of occurrences of an event determined? How
does knowledge of finding the likelihood of an event help you in making
decisions?
TOSS ME UP!
Activity 10
Read the problem carefully then answer the questions that follow.
Jann has a 5-peso coin in his pocket.
1. He tosses the coin twice.
a. How many possible outcomes are there? _____
b. What are those possible outcomes? _____
c. What is the probability of both tails turning up? _____
2. He tosses the coin thrice.
a. How many possible outcomes are there? _____
b. What are those possible outcomes? _____
c. What is the probability of getting at least two heads? _____
EMILIO
AGUINALDO
2013

577
LET’S TOSS AND ENJOY…
Activity 11
Play “Snake and Ladder” with a friend, then answer the questions below.
1. Roll the die once.
a. How many possible outcomes are there? _______
b. What are those outcomes? _______
c. If you want to move ahead 4 spaces on the board, then what is the probability
of rolling a 4? _______
d. If your friend wants to move ahead 8 spaces on the board, then what is the
probability of rolling an 8?_____ Why? _____
2. Roll the die twice.
a. How many possible outcomes are there? _______
b. What is the probability of having “doubles”? _______
c. What is the probability of getting a set of outcomes whose sum is greater
than 10? ______
MY FATHER SOLVED WITH ME
Activity 12
Parents love working with their children. At home, invite your father or
mother to toss an icosahedron which has congruent faces numbered 1 to
20 then read and answer together all the questions that follow.
Your father rolled the icosahedron once.
1. How many possible outcomes are there? _______
2. What are those possible outcomes? ______________________
3. What is the probability that the face which lands up is 25? _______
How will you interpret your answer? _______________________________
4. What is the probability that the face which lands up is an odd number? _______
5. What is the probability that the face which lands up is an even number divisible by
4? ______
6. What is the probability that the face which lands up is a positive number?
How did you arrive at your answer? Explain. ___________________________

578
I’M DREAMING OF A NEW CELL PHONE
Activity 13
Analyze carefully the problem, then answer what is asked for.
One of your dreams is to have a new cell phone. You went to a cell phone dealer and
he gave you the following options. How many available cell phones could you choose from?
Brands:

L

O

V

E
Colors: white (W), red (R), yellow (Y), gray (G), blue (B)
Models: X, K, P
1. How many brands are there? ____________
2. How many colors are available? ____________
3. How many models are given? ____________
4. Show the tree diagram which can be used to find the total number
of choices.

5. Based on the illustration, how many available cell phones could you
choose from? _________
6. By doing simple calculation, how will you get the total number of
choices?
Write the correct expression, then solve for the total choices.
Expression Solution

QU
ESTIO
NS
?

579
MATCH ME WITH THE PROBABILITY SCALE
Activity 14
Match the following with each letter on the probability line. Number 1 is done for you.
a b c d e
Impossible Unlikely Even Chance Likely Certain
0 0.25 0.5 0.75 1
e 1. There are 7 days in a week.
____ 2. Out of 20 items, Jann got 15.
____ 3. In the Philippines, it will snow in March.
____ 4. If you flip a coin, it will come down heads.
____ 5. All months of the year have 28 days.
____ 6. It will be daylight in Manila at midnight.
____ 7. The day before Monday is Sunday.
____ 8. Of the 40 seedlings, only 10 survived.
____ 9. Next year, the month after November has 30 days.
____ 10. The third person to knock on the door will be a female.
____ 11. The chance that the last outcome in rolling a number cube is an even number.
In this section, the discussion was about problems involving probabilities of events
and fundamental counting principles.
What new realizations do you have about the topic? What new connections have you
made for yourself?
Now that you have a deeper understanding of the topic, you are ready to do the tasks
in the next section.
What to TransferWhat to Transfer
Your goal in this section is to apply your learning to real life situations. You will be
given practical tasks which will demonstrate your understanding. After answering a lot of
exercises, I’m sure you’re now ready to give your insights on the following questions:

How is the number of occurrences of an event determined? How does
knowledge of finding the likelihood of an event help you in making decisions?

580
LET’S HELP THEM ENJOY THEIR
VACATION IN BORA!
Activity 15
Read the following carefully then perform the task diligently.
The family plans for a three-day summer vacation in Boracay. The challenge is to present
variety of transportation packages within the allotted budget of the family. Create a variety of
transportation options for the family to choose from. Explain how you arrived at these options.
Rubric on the Group Work for Transportation Packages
4 3 2 1
Visual Appeal
Neat, readable,
correctly labeled
diagram, and
has a very
creative
design that
enhances the
diagram
Neat, readable,
correctly labeled
diagram, and
has a creative
design
Readable
and correctly
labeled
Messy
Computation of
Charge
Correct and
detailed
Detailed but with
minor errors
Detailed but with
major
errors
Not detailed
Proposal
Based on
correct equation
and computation
Based on
mathematical
computation
Based on sound
mathematical
reasoning
without
computation
Based on
guessing

581
LET’S CONVINCE THE COMMUNITY!
Activity 16
Situation:
The barangay officials want the community folks especially the students and youth to
be informed/educated about engaging in games of chance (those found in the local
carnivals). They invited a game analyst to convince the people in the community that they
should be mindful of their chances of losing and winning in these types of games so that
they will not end up wasting their time and money. The game analyst needs to present
and disseminate this during the barangay monthly meeting. The presentation should
meet the following standards: use of mathematical concepts, accuracy, organization,
and delivery. Please refer to the Performance Task rubrics.
Activity:
Consider yourself as the game analyst invited by the barangay officials to make an
educational presentation on how to convince the community folks of their chances in
losing and winning in those games in the local carnival. The presentation should meet
the set standards.
Goal:
The problem or challenge is to inform/educate the people, especially the students and
youth in a community about engaging in games of chance (those found in the local
carnivals and the like).

Role:
You are a game analyst invited by the barangay officials.
Audience:
The target audience are the barangay officials and the people in the community.
Situation:
You need to convince the people in the community that they should be mindful of their
chances of losing and winning in these types of games so that they would not end up
wasting too much of their time and money.
Product/Performance:
You need to create a presentation for the monthly barangay/community forum/meeting
in order to disseminate the information.
Standards:
The presentation should meet the following standards: use of mathematical concepts,
accuracy, organization, and delivery.

582
PERFORMANCE TASK RUBRICS
CRITERIA
OUTSTANDING
4
SATISFACTORY
3
DEVELOPING
2
BEGINNING
1
USE OF
MATHEMATICAL
CONCEPTS
It shows in-depth
understanding
of the required
mathematical
knowledge in
probability. The
solution completely
addresses all
mathematical
components
presented in the
task.
It shows
understanding
of required
mathematical
knowledge. The
solution addresses
most of the
mathematical
components
presented in the task.
It shows some
understanding
of the required
mathematical
knowledge.
The solution
addresses
some of the
mathematical
components
presented in the
task.
It shows no
understanding
of the problem,
perhaps only
re-copying the
given data.
The solution
addresses
none of the
mathematical
components
required to
solve the task.
ACCURACY 100% of the steps
and solutions have
no mathematical
errors.
Almost all (85 - 89%)
of the steps and
solutions have no
mathematical errors.
Most (75-84%)
of the steps and
solutions have
no mathematical
errors.
More than 75%
of the steps
and solutions
have
mathematical
errors.
ORGANIZATION It uses an
appropriate and
complete strategy for
solving the problem.
It uses clear and
effective diagrams
and/or tables.
It uses a complete
strategy for solving
the problem. It uses
creative diagrams
and/or tables.
It uses an
inappropriate
strategy or
application
of strategy is
unclear. There
is limited use
or misuse of
diagrams and/or
tables.
It has no
particular
strategy for
solving the
problem. It
does not show
use of diagrams
nor tables.
DELIVERY There is a clear and
effective explanation
of the solution. All
steps are included
so the audience
does not have to
infer how the task
was completed.
Mathematical
representation
is actively used
as a means of
communicating
ideas, and precise
and appropriate
mathematical
terminology.
There is a clear
explanation
and appropriate
use of accurate
mathematical
representation.
There is effective
use of mathematical
terminology.
There is an
incomplete
explanation; it
is not clearly
represented.
There is
some use of
appropriate
mathematical
representation
and terminology
for the task.
There is no
explanation of
the solution.
The explanation
cannot be
understood, or
is unrelated to
the task. There
is no use or
inappropriate
use of
mathematical
representation
and terminology
for the task.

583
REFLECTION JOURNAL
Activity 17
In this section, your task was to apply what you have learned in this module in real-
life situation.
How did you find the performance task? How did the task help you see the real world
use of the topic?
You have completed this lesson in probability. Before you go for a summer vacation,
you have to answer the following post–assessment.
In this module, you learned concepts which helped you accomplished the different
tasks successfully. This time, kindly answer this activity which would show how important this
module is in your day-to-day activities.
In this module, I learned about
I can use these concepts
These are very important because
I understand that
I can use the basic concepts of probability and the fundamental counting principles
in my day-to-day activities by

584
In this lesson, I have understood that ______________
________________________________________________
________________________________________________
_________________________________________________
________________________________________________
________________________________________________
________________________________________________
________________________________________________
________________________________________________
_________________________________________________
________________________________________________
_________________________________________________
________________________________________________
___________.
REFLECTIONREFLECTION

585
SUMMARY/SYNTHESIS/GENERALIZATION
This module was about the basic concepts of probability and the fundamental counting
principles.Inthismodule,youwereencouragedtodiscoverbyyourselftheoperational definition
of concepts, the difference between experimental probability and theoretical probability and
the importance of the fundamental counting principle. The knowledge and computational skills
gained in this module help you solve real-life problems involving probabilities of events which
would lead you to make better decisions in life and to perform practical tasks at your best.
GLOSSARY OF TERMS USED IN THIS MODULE:
Certain refers to an event which has to happen.
Chance refers to the“ likelihood” that something will happen.
Dependent events are events in which one event affects the outcome of another.
Die is a small cube whose faces are marked with dots of 1, 2, 3, 4, 5, and 6 in each of the 6
faces.
Equally likely events are events that have the same probability of occurring.
Experiment activities such as tossing or flipping a coin, rolling a die, or picking a card from
a standard deck of cards without looking which could be repeated over and over again and
which have well-defined results.
Experimental probability is the probability of an outcome of an event based on an experiment.
The more trials done in an experiment, the closer the experimental probability gets to the
theoretical probability.
Fundamental Counting Principle states that we can find the total number of ways different
events can occur by multiplying the number of ways each event can happen. If we have x
ways of doing event 1, y ways of doing event 2, and z ways of doing event 3, then we can
find the total number of ways of doing events1, 2, and 3 by getting the product of x, y, and z.
Icosahedron is a three-dimensional geometric figure made up of 20 sides or faces.
Impossible refers to an event which will never happen.
Independent events are two events which do not affect the outome of each other.
Outcomes are the results of experiments.

586
Probability is branch of mathematics that deals with uncertainty. It is a measure or estimation
of how likely it is that an event will occur.
Probability Rules:
1. The probability of any event is a number (either a fraction, a decimal, or a percent)
between and including 0 and 1.
2. If an event will never happen, then its probability is 0.
3. If an event is sure to happen, then the probability is 1.
4. The sum of the probabilities of all the outcomes in the sample space is 1.
Sample point is an individual outcome in the sample space.
Sample space or probability space in the set of all possible outcomes of an experiment.
Theoretical probability is the probability that a certain outcome will occur as determined
through reasoning or calculation.
Tree diagram is a device consisting of line segments emanating from a starting point and from
the outcome point. It is used to determine all possible outcomes of a probability experiment.
Uncertain refers to something which is likely to change, and therefore not reliable or stable.
Unlikely refers to something which is not likely to occur, not likely to be true or be believed.
REFERENCES AND WEBSITE LINKS USED IN THIS LESSON:
REFERENCES
Acelajado, Maxima J. ( 2008 ). Intermediate Algebra. pp.319 -326. Makati City, Philippines.
Diwa Learning Systems Inc.
Basilio, Faith B., Chua, Edna A., Jumawan, Maria T., Mangabat, Lawrence Oliver A., Mendo-
za, Mario B., Pacho, Elsie M., Tamoria, Ferdinand V., Villena, Eufrosina S.,Vizcarra, Florante
O., Yambao, Teresa M. (2003). Fundamental Statistics. Philippines. pp. 129 -133. Trinitas
Publishing Inc.
Garcia, George A. (2003). Fundamental Concepts and Methods in Statistics (Part 1). pp. 4 – 9.
Manila, Philippines. University of Sto. Tomas Publishing House.

587
Garcia, George A. (2004). Fundamental Concepts and Methods in Statistics (Part 2). pp. 8 – 43.
Manila, Philippines. University of Sto. Tomas Publishing House.
Glencoe/McGRAW-HILL. (1986). Mathematics Skills for Daily Living. pp. 397 - 411. United
States of America. Laidlaw Brothers, Publishers.
Price, Jack/ Rath, James N./ Leschensky, William.(1989). Pre- Algebra, A Problem Solving
Approach. pp. 420 – 430. Columbus, Ohio. Merrill Publishing Co.
WEBSITE LINKS
Copyright 2011MathsIsFun.com
www.mathsisfun.com/definitions/probability.html
These sites provide the picture of the probability line and definitions of the basic concepts.
http://intmath.com/counting-probability/2-basic-principles-counting.php
This site provides the picture for Activity 2, notes/tips on the basic counting principles.
http://whatis.techtarget.com/definition/probability
This site provides the definition of probability and other concepts.
www.algebra-clss.com/probability-problems.html
This site provides notes, pictures, and examples of independent/dependent events.
www.algebra-class.com/theoretical-probability.html
This site provides notes, pictures, and examples of Experimental Probability and Theoretical
Probability.
http://www.onlinemathlearning.com/theoretical-probability.html
This site provides a video lesson on experimental and theoretical probability.
www. Learningwave.com/chapters/probability/dependent_independent.html
This site provides examples of dependent and independent events,
http://www.mathworksheets4kids.com
This site provides exercises/ worksheets for the students to answer.
http://www.algebra-class.com/fundamental-counting-principle.html
This site provides the formula and examples of Fundamental Counting Principle.
www.virtualnerd.com/algebra-2/probability-statistics/fundamental-counting-principle-defini-
tion.php
This site provides a video lesson on Fundamental Counting Principle.

588
http://www.aaaknow.com/sta-basic-cntg.htm
This site provides notes on basic counting principles and practice exercises on finding the
total possible outcomes.
http:// mathgoodies.com/lessons/vol16/intro-probability.html
This site provides examples and items for the Pre/Post Assessment.
http:// www.mathwire.com/games/datagames.html
This site provides enrichment games on Probability.
This site provides the formula and examples of Fundamental Counting Principle.
www.virtualnerd.com/algebra-2/probability-statistics/fundamental-counting-principle-defini-
tion.php
This site provides a video lesson on Fundamental Counting Principle.

Mathematics 8 Basic Concepts of Probability

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