experimental designs Flashcards
What is meant by experimental deisgn?
the different ways in which ppts can be organised in relations to experimental conditions.
what are the 3 experimental designs?
independent groups, repeated measures, matched pairs
What is an independent groups design?
when two seperate groups of ppts experience two different conditions of the experiment
What is repeated measures design?
all ppts take part in both conditions of the experiment
What is a matched pairs design?
pairs of ppts are matched on a variable/s that could affect the DV, then split into two conditions
What are the strengths of indpendent groups? (2)
Order effects are not an issue
Demand characteristics are less likely
What are the weaknesses of independent groups? (1)
Participant variables could be an issue, as they may not be shared by both groups and therefore could affect the DV (validity)
what are the strengths of repeated measures? (2)
particpant variables are more controlled, increasing validity
more econonomical, less participants are needed to carry out the study
what are the weaknesses of repeated measures? (2)
order effects, participating in one conditions may cause lasting effects when completing the other condition
ppts are more likely to guess the aim of the study when doing both conditions
what are the strengths of matched pairs? (1)
order effects and deman characteristics are less of a problem
what are the weaknesses of matched pairs? (2)
ppts can never be matched ecxactly, therefore ppt variables cannot be fully controlled
matching can be time consuming and expensive
What is random allocation?
An attempt of controlling ppt variables which ensures that each ppt has the same chance of being in one condition as any other
What is counterbalancing?
An attempt of controlling order affects, half of ppts experience condition A, then B, other half experience B, then A.
