Chapter 13 Flashcards
When can quasi experiments be useful?
1) Practicalities: random assignment of subjects to conditions may not be possible.
2) Interest in subject variable: a characteristic of subjects on which they have been selected.
3) External validity: study subjects or settings that are more appropriate to question of interest
What is the major weakness of Quasi experiments?
Not able to control the ‘who’ of an experiment
often data must be collected at a particular time or not at all.
presence of confounded variables reduces the internal validity.
What is the Nonequivalent Control group?
includes both an experimental and control group but subjects are not randomly assigned to groups
most common quasi-experimental design.
Nonequivalent control group with pretest and post-test
both groups are tested before and after the change in conditions for the experimental group
What is an interrupted time series design?
group is compared over time by considering trend of data before and after experimental manipulation
similar rationale to single-subject AB design
better than one-group pretest-posttest design because it analyzes trends
quasi-experimental because researcher has little to no control over when conditions change
what are repeated treatment designs?
Design in which treatment is withdrawn and then presented a second time.
What is meta analysis?
A meta-analysis is a statistical analysis that combines the results of multiple scientific studies.
