Chapter 10: Within-Subjects Design Flashcards
What occurs in a pretest-posttest design?
the dependent variable is measured before and after exposing participants to a treatment or intervention
T or F: a pretest-posttest deign is an example of a between-subjects deign
FALSE; it is a within-subjects design
What is another type of within-subjects design where each participant is exposed on each level of the dependent variable?
repeated-measures design
What are 2 advantages of within-subjects design? Explain them:
- Statistical Power
- with the same participants in every condition, we don’t have to worry about individual differences between groups - Efficiency
- LESS participants are needed
What is a type I error (alpha error)?
When we reject the null hypothesis (even though we should accept it)
- the results simple occured by chance
ex. Saying an innocent person is guilty
What is a type II error (beta error)?
When we accept the null hypothesis (even though we should reject it)
- there WAS a significant finding, but it was missed in the analysis
ex. Letting a guilty person go because you think they are innocent
What are 4 threats to internal validity?
- maturation
- attrition/mortality
- history
- testing
What is maturation, and how can we prevent it?
when a change emerges spontaneously over time
solution: use a control group that has NO therapy/intervention to determine is maturation is a potential threat
What is attrition/mortality, and how can we prevent it?
differential dropping out of participants from a study
solution: make continuation in the study appealing and nonthreatening OR remove them from the pretest data
What is history, and how can we prevent it?
an external event that potentially influences participants’ behavior
solution: difficult to prevent; take researcher notes of any unexpected change
What is the testing effect, and how can we prevent it?
participants’ scores on future measurements can change due to increased familiarity with the dependent measure
solution: use distractor items or tasks, increase time between the different conditions
What is the fatigue effect?
when there is a deterioration in measurements due to participants becoming tired and less aware during the study
What is the practice effect?
participants seem to improve simply because they have more practice completing the dependent variable measures
solution: provide participants with extensive training on the task before starting the actual study & running a trial test so participants can learn and improve before the measurement begins
What are 3 ways to potentially prevent/control order effects? Explain each one
- randomizing the order of levels
- the sequence of experimental conditions is changed, so it is different for every participant - counterbalancing/systematic
- all potential treatment sequences are identified and THEN, each sequence is randomly assignmed to participants - latin square design
- counterbalancing strategy where each experimental condition appears at every position in the sequence order
- you only use as many possible sequences as we have experimental conditions
What type of design do we use if we have 4 or more levels?
latin-square design
What is “Schadenfreude”?
pleasure at the misfortune of others
What type of problem threatens internal validty because there is a change in how a variable is measured/administered during the study?
instrumentation problem
What does a dependent means t-test (AKA paired-samples t-test) evaluate?
evaluates whether the difference between participants’ pretest and posttest scores significantly differ from zero (no difference). If it does differ, we can conclude there was a statistically significant change between pretest and posttest scores
What is a repeated-measures ANOVA?
a statistic used to test a hypothesis from a within-subjects deign with 3 or more conditions
**if there is a significant difference, we can then use post-hoc tests
A professor wants to assess the impact that a newly developed first-year seminar has on the academic perseverance and motivation of new first-year students. The professor measures first-year students’ academic perseverance and motivation on the first day of class and again on the last day of class. What is an obvious threat to the internal validity of this pretest-posttest study?
a) attrition
b) maturation
c) testing effects
d) instrumentation problems
b) maturation
Dr. smith notices that the students he already had for one course tend to do better in subsequent courses of his. Which of the following order effects is mot likely NOT a possible reason for this finding?
a) sensitization effect
b) practice effect
c) carryover effect
d) fatigue effect
d) fatigue effect
Deception might be a useful strategy for minimizing which of the following potential order effects in a repeated-measures design?
a) fatigue effects
b) sensitization effects
c) carryover effects
d) practice effect
b) sensitization effects
Challenges with scheduling participants for a study multiple times may lead some participants to drop out of a within-subjects experimental design. This could possibly rise to which threat to internal validtiy?
a) history
b) maturation
c) attrition
d) intrumentation
c) attrition
Attrition, or _____, is a threat to ______ validity
a) maturation; internal
b) maturation; external
c) mortality; internal
d) mortality; external
c) mortality; internal
A repeated-measures design differs from a pretest-posttest design in that unlike the pretest-posttest design, the repeated-measures design:
a) is a within-subjects design
b) is a between-subjects design
c) studies the same individuals more than once
d) lacks a baseline measurement
d) lacks a baseline measurement
Which threat to internal validity occurs when the sequence of experimental conditions affects the dependent measure?
a) order effect
b) maturation effect
c) instrumentation effect
d) history effect
a) order effect
Misleading participants about the true purpose of a study will MOST reduce which type of order effect?
a) practice
b) fatigue
c) sensitization
d) carryoverr
c) sensitization
A within-subjects experimental design has 4 conditions. Each participant will be exposed to each condition exactly once. How many possible orders of conditions are there?
a) 4
b) 12
c) 24
d) 36
c) 24
A within-subjects experimental design has 4 conditions (A,B,C,D). Which sequence would NOT occur in a Latin square design?
a) ABCD
b) BCDA
c) CDBA
d) DCBD
d) DCBD (***THERE IS NO A)
A dependent means t-test determines if the differences between scores on the pretest and posttest measures differ significantly from
a) 0
b) 1
c) .05
d) a previously obtained baseline score
a) 0
Which statistic is used to determine if there is a significant diffference between 3 or more sets of related scores>
a) t-test for independent means
b) t-test for dependent means
c) ANOVA
d) repeated-measures ANOVA
d) repeated-measures ANOVA
Which statistic is used to determine if there is a significant difference between two sets of related scores?
a) t-test for independent means
b) t-test for dependent means
c) ANOVO
d) repeated-measures ANOVO
b) t-test for dependent means
