PSYC 3650 EXAM 4 REVIEW QUESTIONS
Confounding/Extraneous Variables - Answers - third variables that affects results. They
are the enemy of internal validity
Examples: time of day, placebo effects, study conditions
Random Assignment - Answers - helps increase causation, equal groups, and erase
differences between groups before study
Probable Cause (checking three boxes) - Answers - no differences between groups at
the beginning, no differences during, only differences at the end. The only difference
should be independent variations.
Identifying IV - Answers - manipulated by researchers
Identifying DV - Answers - what we are measuring
Testing Effects - Answers - participants tested twice on the same behavior can cause a
source of bias. For example, if a Ps completes a puzzle the first time, their second time
timing/accuracy will be better on same puzzle.
How to control it: Solomon Four-Group Design
Solomon Four-Group Design - Answers - Special pretest-posttest and posttest only
design using 4 groups (2 treatment, 2 control) to test if the pretest influences the
treatment effects.
If there is test effect, experimental groups should differ from control groups at posttest. If
there is no difference, then no testing effects
Order Effects - Answers - occur when the order in which the participants experience
conditions in an experiment affects the results of the study. If Ps does a difficult task at
first, then second task will seem too easy.
How to control Order Effects - Answers - To solve this problem, order can be
counterbalanced, different groups of participants receive different orders, helps
determine if the effect of IV depends on order.
Main effects of Factorial Designs - Answers - Provide a test of the independent effect of
each IV on the DV, if two lines are parallel then no interaction
True Independent Variables - Answers - must be manipulated by experimenters,
random assignment is included, no pre-existing differences between groups
Confounding/Extraneous Variables - Answers - third variables that affects results. They
are the enemy of internal validity
Examples: time of day, placebo effects, study conditions
Random Assignment - Answers - helps increase causation, equal groups, and erase
differences between groups before study
Probable Cause (checking three boxes) - Answers - no differences between groups at
the beginning, no differences during, only differences at the end. The only difference
should be independent variations.
Identifying IV - Answers - manipulated by researchers
Identifying DV - Answers - what we are measuring
Testing Effects - Answers - participants tested twice on the same behavior can cause a
source of bias. For example, if a Ps completes a puzzle the first time, their second time
timing/accuracy will be better on same puzzle.
How to control it: Solomon Four-Group Design
Solomon Four-Group Design - Answers - Special pretest-posttest and posttest only
design using 4 groups (2 treatment, 2 control) to test if the pretest influences the
treatment effects.
If there is test effect, experimental groups should differ from control groups at posttest. If
there is no difference, then no testing effects
Order Effects - Answers - occur when the order in which the participants experience
conditions in an experiment affects the results of the study. If Ps does a difficult task at
first, then second task will seem too easy.
How to control Order Effects - Answers - To solve this problem, order can be
counterbalanced, different groups of participants receive different orders, helps
determine if the effect of IV depends on order.
Main effects of Factorial Designs - Answers - Provide a test of the independent effect of
each IV on the DV, if two lines are parallel then no interaction
True Independent Variables - Answers - must be manipulated by experimenters,
random assignment is included, no pre-existing differences between groups
