Experimental designs Flashcards
what are experimental designs
the ways in which ppts are used in experiments
what are the types of experimental designs
- independent groups
- repeated measures
- matched pairs
what is independent groups
two separate groups experience two separate -conditions of the experiment and results are compared
what are the strengths of independent groups
- less demand characteristics
- easy to draw comparisons in results analysis
what are the weaknesses of independent groups
- different variables in each group
- less validity
- costly/time consuming
what is repeated measures
all ppts experience both conditions of the experiment
what is a strength of repeated measures
- participant variables are controlled so higher validity
- fewer ppts are needed so less time spent recruiting them
what is a weakness of repeated measures
- more demand characteristics
- more confounding variables
what design involves counterbalancing
repeated measures
what is counterbalancing
half ppts experience conditions in one order and the other half in the opposite order
what is matched pairs
similar ppts are paired on participant variables and allocated to condition A or B
what is a strength of matched pairs
- less demand characteristics
- attempt to control confounding variables of participant variables
what is a weakness of matched pairs
- never an exact match- extranous varaiables
- matching may be time consuming and expensive- especially if a pretest is requires it can be less economical
