In an experiment, a researcher manipulates people's mood to determine whether changes in mood cause changes in memory performance. However, the researcher is not sure that the manipulation is really causing people's mood to change. In this case, what should the researcher do?
a. Control mood by holding it constant.
b. Control mood by matching it across treatment conditions.
c. Add a no-treatment control group in which mood is not manipulated.
d. Add a manipulation check by measuring mood.
Tonja wants to evaluate the effects of a new school breakfast program on student conduct and academic achievement. She cannot evaluate every student in every school in the district, so she randomly selects several schools and then collects data on all of the students in those schools. What type of sample is she using?
a. simple random
b. stratified random
c. systematic random
d. cluster random
A researcher performing a cross-lagged procedure would
a. avoid collecting any correlations
b. obtain several correlations at one point in time
c. obtain several correlations over time.
d. refrain from determining which factors lead to other factors.
Ethnicity, gender, and age are all examples of _____ variables.
a. nonmanipulated
b. subject
c. manipulated
d. both nonmanipulated and subject
Which technique provides useful information when there are small changes from one treatment condition to another, when simulations are used or when a placebo is used?
a. random selection
b. random assignment
c. no-treatment controls
d. manipulation checks
In what type of sample would you divide the sample into groups, typically along geographic lines, randomly select groups, and then measure all units within the sampled groups?
a. simple random
b. stratified random
c. systematic random
d. cluster random
A researcher studying productivity among factory workers finds that productivity declines as the outside temperature increases. This is an example of
a. a negative correlation
b. a zero correlation
c. a positive correlation
d. a confound
When using a _____ variable, subjects are _____ assigned to groups.
a. nonmanipulated independent; randomly
b. nonmanipulated independent; not randomly
c. subject; randomly
d. manipulated independent; not randomly
A researcher exposes people to a stressful situation (such as public speaking) to examine the effect of stress on depressed mood. The researcher includes a measure of stress as a ____.
a. measure of the dependent variable
b. measure of extraneous variables
c. control for confounding variables
d. manipulation check
A sampling method where you determine randomly where you want to start selecting in the sampling frame and then follow a rule to select every xth element in the sampling frame list is called a ____ method.
a. simple random
b. stratified random
c. systematic random
d. cluster random
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