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Research Design Explained

Mark L. Mitchell, Janina M. Jolley

Chapter 5

Measuring and Manipulating Variables: Reliability and Validity - all with Video Answers

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Chapter Questions

Problem 1

Why is bias considered more serious than random error?

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01:26

Problem 2

What are the two primary types of subject bias? What are the differences between these two types?

Emily Himsel
Emily Himsel
Numerade Educator
01:10

Problem 3

Suppose a "social intelligence" test in a popular magazine had high internal consistency. What would that mean? Why would you still want to see whether the test had discriminant validity? How would you do a study to determine whether the test had discriminant validity?

Emily Himsel
Emily Himsel
Numerade Educator
03:39

Problem 4

Given that IQ tests are not perfectly reliable, why would it be irresponsible to tell someone his or her score on an IQ test?

James Kiss
James Kiss
Numerade Educator
01:16

Problem 5

What is content validity? How does it differ from internal consistency? For what measures is it most important?

Emily Himsel
Emily Himsel
Numerade Educator
04:17

Problem 6

Swann and Rentfrow (2001) wanted to develop a test "that measures the extent to which people respond to others quickly and effusively." In their view, high scorers would tend to blurt out their thoughts to others immediately and low scorers would be slow to respond.
a. How would you use the known-groups technique to get evidence of your measure's construct validity?
b. What measures would you correlate with your scale to make the case for your measure's discriminant validity? Why? In what range would the correlation coefficients between those measures and your measure have to be to provide evidence of discriminant validity? Why?
c. To provide evidence of convergent validity, you could correlate scores on your measure with a behavior typical of people who blurt out their thoughts. What behavior would you choose? Why?

Jennifer Stoner
Jennifer Stoner
Numerade Educator
00:44

Problem 7

A researcher wants to measure "aggressive tendencies" and is trying to decide between a paper-and-pencil test of aggression and observing actual aggression.
a. What problems might there be with observing aggressive behavior?
b. What would probably be the most serious threat to the validity of a paperand-pencil test of aggression? What information about the test would suggest that the test is a good instrument?

Jessica Reyna
Jessica Reyna
Numerade Educator
04:17

Problem 8

Think of a construct you would like to measure.
a. Name that construct.
b. Define that construct.
c. Locate a published measure of that concept (if you are having trouble finding a published example, see Web Appendix B), and write down the reference for that source.
d. Develop a measure of that construct.
e. What could you do to improve or evaluate your measure's reliability?
f. If you had a year to try to validate your measure, how would you go about it? (Hint: Refer to the different kinds of validities discussed in this chapter.)
g. How vulnerable is your measure to subject and observer bias? Why? Can you change your measure to make it more resistant to these threats?

Jennifer Stoner
Jennifer Stoner
Numerade Educator
01:40

Problem 9

What problems do you see with measuring "athletic ability" as 40-yard-dash speed? What steps would you take to improve this measure? (Hint: Think about solving the problems of bias and random error.)

Lucas Finney
Lucas Finney
Numerade Educator
00:53

Problem 10

Think of a factor that you would like to manipulate.
a. Define this factor as specifically as you can.
b. Find one example of this factor being manipulated in a published study (if you are having trouble finding a published example, see Web Appendix B). Write down the reference citation for that source.
c. Would you use an environmental or instructional manipulation? Why?
d. How would you manipulate that factor? Why?
e. How could you perform a manipulation check on the factor you want to manipulate? Would it be useful to perform a manipulation check? Why or why not?

AG
Ankit Gupta
Numerade Educator