Psychology 2300: Exam 3 questions
with correct answers 2025/2026
pretest/posttest design (aka one-group) - ANS ✔✔An experiment in which a researcher recruits
one group of participants; measures them on a pretest; exposes then to a treatment,
intervention, or change; and then measures them on a posttest.
"The really bad experiment"
are not; are - ANS ✔✔If the lines _______ (ARE or are NOT?) parallel, there probably is an
*interaction*.
If the lines _______ (ARE or are NOT?) parallel, there probably is *no interaction*.
within-groups - ANS ✔✔Which is more efficient: independent groups design or within-groups
design?
Maturation - ANS ✔✔A threat to internal validity that occurs when an observed change in an
experimental group could have emerged more or less spontaneously over time
Spontaneous change in behavior ("spontaneous remission")
*Solution: Comparison Groups!*
history threats - ANS ✔✔A threat to internal validity that occurs when it is unclear whether a
change in the treatment group is caused by the treatment or by a historical factor or event that
affects everyone or almost everyone in the group
external factor/event changes most members of experimental group
*Solution: Comparison Groups!*
,Regression threat - ANS ✔✔A threat to internal validity related to the regression to the mean, a
phenomenon in which any extreme finding is likely to be closer to its own typical, or mean, level
the next time it is measured (with or without the experimental treatment or intervention)
i.e., when extremely low or extremely high performance at Time 1 is likely to be less extreme at
Time 2 (closer to the average)
Solution: Comparison group
Regression to the Mean - ANS ✔✔Extreme values of a measure at point A in time will be less
extreme when measured again at point B in time.
Usually high or low measures (due to chance)
Problem: Extreme scores sometimes motivate an attempt at treatment, and regression then
looks like a treatment effect.
attrition - ANS ✔✔In a repeated-measures design or quasi experiment, a threat to internal
validity that occurs when a systematic type of participant drops out of a study before it ends.
Systematic "Drop-outs" in your data
Solution: *Compute pretest & posttest scores with only the final sample, removing any
dropouts' data from the pretest group average*
testing threat - ANS ✔✔In a repeated-measures design or quasi experiment, a kind of order
effect in which scores change overtime just because participants have taken the test more than
once; includes practice effects and fatigue effects. Error in the way the stimuli/test is presented.
Type of order effect due to repeated exposures to test (fatigue, practice, sensitivity)
Solution: *Posttest only, Comparison group*
Note: can occur in pretest/posttest design (i.e., independent groups)
, instrumental threats - ANS ✔✔A threat to internal validity that occurs when a measuring
instrument changes overtime from having been used before. (Also called instrument decay)
Inconsistent measurement tool
Problem in what is measuring the DV
Solution: Calibrate or use codebooks (observations); post-test only.
selection-history threat - ANS ✔✔A threat to internal validity that occurs in which a historical or
seasonal event systematically affects only the subjects in the treatment group or only those in
the comparison group, not both.
An outside event or factor systematiccally affects participants at one level of the IV.
Selection-attrition threat - ANS ✔✔A threat to internal validity that occurs in which members
are likely to drop out of either the treatment group or the comparison group, not both.
Participants in one experimental group experience attrition.
observer bias - ANS ✔✔A bias that occurs when observers' expectations influence their
interpretation of the study of the participants' behaviors or the outcome of the study.
Expectations of researcher change interpretation
Solution: Masked design or double-blind experiment
demand characteristics - ANS ✔✔A threat to internal validity that occurs when some cue leads
participants to guess a study's hypotheses or goals. (Also called experimental demand)
Change in behavior from "figuring out" study expectations
Solutions: *Masked design or Double-blind experiment*
with correct answers 2025/2026
pretest/posttest design (aka one-group) - ANS ✔✔An experiment in which a researcher recruits
one group of participants; measures them on a pretest; exposes then to a treatment,
intervention, or change; and then measures them on a posttest.
"The really bad experiment"
are not; are - ANS ✔✔If the lines _______ (ARE or are NOT?) parallel, there probably is an
*interaction*.
If the lines _______ (ARE or are NOT?) parallel, there probably is *no interaction*.
within-groups - ANS ✔✔Which is more efficient: independent groups design or within-groups
design?
Maturation - ANS ✔✔A threat to internal validity that occurs when an observed change in an
experimental group could have emerged more or less spontaneously over time
Spontaneous change in behavior ("spontaneous remission")
*Solution: Comparison Groups!*
history threats - ANS ✔✔A threat to internal validity that occurs when it is unclear whether a
change in the treatment group is caused by the treatment or by a historical factor or event that
affects everyone or almost everyone in the group
external factor/event changes most members of experimental group
*Solution: Comparison Groups!*
,Regression threat - ANS ✔✔A threat to internal validity related to the regression to the mean, a
phenomenon in which any extreme finding is likely to be closer to its own typical, or mean, level
the next time it is measured (with or without the experimental treatment or intervention)
i.e., when extremely low or extremely high performance at Time 1 is likely to be less extreme at
Time 2 (closer to the average)
Solution: Comparison group
Regression to the Mean - ANS ✔✔Extreme values of a measure at point A in time will be less
extreme when measured again at point B in time.
Usually high or low measures (due to chance)
Problem: Extreme scores sometimes motivate an attempt at treatment, and regression then
looks like a treatment effect.
attrition - ANS ✔✔In a repeated-measures design or quasi experiment, a threat to internal
validity that occurs when a systematic type of participant drops out of a study before it ends.
Systematic "Drop-outs" in your data
Solution: *Compute pretest & posttest scores with only the final sample, removing any
dropouts' data from the pretest group average*
testing threat - ANS ✔✔In a repeated-measures design or quasi experiment, a kind of order
effect in which scores change overtime just because participants have taken the test more than
once; includes practice effects and fatigue effects. Error in the way the stimuli/test is presented.
Type of order effect due to repeated exposures to test (fatigue, practice, sensitivity)
Solution: *Posttest only, Comparison group*
Note: can occur in pretest/posttest design (i.e., independent groups)
, instrumental threats - ANS ✔✔A threat to internal validity that occurs when a measuring
instrument changes overtime from having been used before. (Also called instrument decay)
Inconsistent measurement tool
Problem in what is measuring the DV
Solution: Calibrate or use codebooks (observations); post-test only.
selection-history threat - ANS ✔✔A threat to internal validity that occurs in which a historical or
seasonal event systematically affects only the subjects in the treatment group or only those in
the comparison group, not both.
An outside event or factor systematiccally affects participants at one level of the IV.
Selection-attrition threat - ANS ✔✔A threat to internal validity that occurs in which members
are likely to drop out of either the treatment group or the comparison group, not both.
Participants in one experimental group experience attrition.
observer bias - ANS ✔✔A bias that occurs when observers' expectations influence their
interpretation of the study of the participants' behaviors or the outcome of the study.
Expectations of researcher change interpretation
Solution: Masked design or double-blind experiment
demand characteristics - ANS ✔✔A threat to internal validity that occurs when some cue leads
participants to guess a study's hypotheses or goals. (Also called experimental demand)
Change in behavior from "figuring out" study expectations
Solutions: *Masked design or Double-blind experiment*
