Experimental Design Flashcards
Experimental design
Different ways in which the testing of participants can be organised in relation to the experimental conditions
Independent groups
Two separate groups of pps experience two dif conditions of experiment, performance then compared
Repeated measures
All pps experience both conditions of experiment, two sets of data from both conditions compared
Matched pairs
Pps paired together on a variable relevant to the experiment, one pp from each pair allocated to dif condition of experiment
Advantage of independent groups design
-avoids order effects as pps participate in one condition only
Disadvantages of independent groups design
-more pps needed than repeated measures
-participant variables may affect results, the mean difference between the groups may be more to do with individual differences than the IV
How to deal with participant variables in independent groups design
Random allocation of pps to the different groups, evenly distributed pps characteristics
Advantages of repeated measures design
-participant variables reduced as performance is being measured against their own performance in the other condition
-needs less people which saves time
Disadvantages of repeated measures design
-Order effects- when the order of conditions has an effect on behaviour, may perform better in second condition as know what to do. Acts as a confounding variable.
-demand characteristics as may work out aim of the study
How to deal with order effects
Counterbalancing- half pps do conditions in one order and the other half in the other order and calculate mean for scores, attempts to balance out order effects
Advantages of matched pairs design
-reduces effect of participant variables as pps performance will be compared with the performance of a pp with similar abilities
-avoids order effects as each pp only participates in one condition
Disadvantages of matched pairs design
-if one pp drops out=lose two pps data
-time consuming and expensive to match pairs
-impossible to match exactly
