schultz10e_ch02.ppt

Schultz & Schultz 10e 1
Copyright © 2010 Pearson Education, Inc.,
Upper Saddle River, NJ 07458. All rights reserved
Psychology and Work Today

Learning Objectives
After reading this chapter, you should be able to:
• Understand the requirements, limitations, and methods
of psychological research
• Explain the experimental method, how to design an
experiment, and how to select participants for research
• Explain the use of naturalistic observation, polls, and
surveys to collect data
• Describe how to construct a representative sample
• Understand the basic concepts in descriptive statistics,
inferential statistics, and meta-analysis

Why Study Research Methods?
• You will probably have to deal with the
findings of I-O psychologists
• To use their advice you must understand
how they studied the problems and
arrived at their conclusions
• The goal of this chapter is to acquaint you
with the requirements, limitations, and
methods of the scientific approach

Psychological Research
• Objective observation
• Base conclusions on objective evidence
• Control
• Possible extraneous influences on outcomes
should be identified and measured
• Duplication and verification
• Replication of earlier studies

Research Limitations
• Not all behavior can be studied
• Observing behavior can change it
• The Hawthorne effect
• Artificial settings
• College students as subjects

Research Methods
• Experiments
• Naturalistic observations
• Polls and surveys
• Web-based research

The Experimental Method
• The scientific way to determine the effect
or influence of a variable on the subjects’
performance or behavior
• Independent variable
• the stimulus variable that is manipulated to
determine its effect on the subjects’ behavior
• Dependent variable
• the resulting behavior of the subjects, which
depends on the manipulation of the independent
variable

Designing An Experiment:
Effects of Lighting on Productivity
• Lighting
• Production rate
• Elements of control
• Experimental group – exposed to the independent
variable
• Control group – not exposed to the independent
variable, but similar in every other way

Selecting Participants
• Control group and experimental group
must be as similar as possible
• Random group design
• Subjects assigned at random to experimental and
control groups
• Matched group design
• Subjects in one group are matched with subjects
in the other group on characteristics that could
affect their performance
• Desirable, but costly and time consuming

Effect of Training on Turnover &
Productivity
• Subjects
• 208 employees in lingerie factory
• Dependent variables
• Turnover and productivity
• Level of training
• Group 1: 1-day of training (control)
• Group 2: 2-days in training facility
• Group 3: 3-days in training facility
• Group 4: 3-days mixed training (facility & OJT)

Effect of Training on Turnover &
Productivity
• Results
• Turnover was lowest in Group 3, but so was
productivity
• Turnover was almost as low in Group 4, and
productivity was nearly as high as in the control
group

Naturalistic Observation
• Observation of behavior in natural setting
without experimental manipulation of
independent variable
• Avoids artificiality – observed behaviors are
typical of what naturally happens
• However, without manipulations of IVs, it is
difficult to conclude what brought about
change
• The observation cannot be repeated
• Observer effects

Naturalistic Observation of
Store Clerks
• Subjects
• 1,319 clerks in 576 convenience stores
• Observations were made on levels of
courtesy, which were then related to sales
• Findings
• the higher the incidence of courteous
behaviors, the lower the sales
• the busier the store, the less time the clerk had
to exhibit courteous behaviors

Surveys and Opinion Polls
• Survey research method relies on
interviews, behavioral observations, and
questionnaires to sample what people
say
• Focus is not on what people do, but what
they say they do

The Problems with Surveys
• Difficult to measure precisely our
personal opinions and attitudes
• Some people deliberately lie
• Socially or politically correct response
• Give an opinion on the subject even if they don’t
have one
• People more likely to be honest when in private
• Difficult to find people to respond
• Phrasing of the question often influences the
response

Ways to Collect Survey Data
• Personal interviews
• Paper and Pencil Questionnaires
• Web-based surveys
• Most frequently used approach to employee
polling
• More reliable than telephone surveys
• Subject to “ballot stuffing”
• Telephone surveys
• Problems arising from increased cell phone use

Basic Types of Survey Questions
• Open-end
• Respondents state their views in their own words
• Fixed-alternative
• Respondents must limit their answers to the choices
presented
• simplifies the process
• may not completely reflect respondents’ range of opinions
• It’s a good idea to pretest the questions on a
small sample

Methods for Constructing a
Representative Sample
• Probability sampling
• Each person in the population has a
known probability of being included in the
sample
• Quota sampling
• Because the sample must reflect the
proportions of the larger population,
quotas are established for categories such
as age, gender, and ethnic origin

Web-Based Research
• Advantages
• Can be conducted 24/7
• Faster, less costly
• Availability of larger, more diverse pool of
participants
• Direct data entry reduces coding costs and errors
• Disadvantages
• Impossible to assess honesty on demographics
• Range restriction – more educated, affluent people
have computer access
• Lower response and higher drop-out rates
• http://psych.hanover.edu/research/exponnet.html

Methods of Data Analysis
• Descriptive statistics
• Ways of describing research data in a
concise, meaningful manner
• Inferential statistics
• Used to compare performance levels of the
experimental group and the control group
• Meta-analysis
• The large scale reanalysis and averaging of
the results of previous research studies

Presentation of Descriptive
Statistics
• Graphs
• Measures of central tendency
• Mean
• Median
• Mode
• Measures of variability
• Standard deviation
• Correlation coefficient

Measures of Central Tendency
• Mean
• Arithmatic average
• Median
• The score at the midpoint of a statistical
distribution
• Mode
• The most frequently obtained score in
the distribution of data
EXAMPLE
Data: 1,1,1,1,1,2,2,3,3,3,3,5,5
Mean = 2.38; Median = 2; Mode = 1

• Standard Deviation (SD)
• It is a precise distance along the distribution’s
baseline
• Using the SD, we can determine the
percentage of scores that fall above or below
any particular raw score
• Correlation
• The relationship between two variables
• strength of relationship
• direction of relationship
Measures of Variability

Sample Distributions
• Normal Distribution
• Bell-shaped with most scores falling toward
the middle with few at high and low extremes
• Mean, median and mode are equal
• Skewed Distribution
• Asymmetrical with more scores falling closer
to high or low extremes
• Median is most useful
measure of central tendency
because it is less affected
by extreme scores

The Normal Distribution of IQ

Graphing a Correlation
x
y
x
y
x
y
Positive Correlation
Negative
Correlation
No
Correlation

Inferential Statistics
• Methods for analyzing data that express
relationships (e.g., differences between groups)
in terms of probabilities
• Statistical significance
• The level of confidence we have in the results of an
experiment based on probability values
• Probability
• The idea that a difference between the means of
experimental and control groups could have occurred by
chance
• If P=.01, a difference would occur by chance only 1 time
out of 100.

Meta-Analysis
• The large scale reanalysis of the results
of previous studies
• The average effect size of multiple studies
weighted by sample size
• Helps to determine overall trends
• Used to reach more objective conclusions
where a large body of research exists

Key Terms
• Control group
• Correlation coefficient
• Descriptive statistics
• Experimental group
• Experimental method
• Fixed-alternative survey
questions
• Inferential statistics
• Matched group design
• Mean
• Median
• Meta-analysis
• Mode
• Naturalistic observation
• Normal distribution
• Open-end Survey
Questionnaire
• Probability
• Probability sampling
• Quota sampling
• Scientific method
• Skewed distribution
• Standard deviation
• Statistical significance
• Survey research method

schultz10e_ch02.ppt

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