Experimental designs

Question 1

Experimental design

Answer 1

The way in which px’s are used in experiments.

Question 2

Independent groups

Answer 2

Two separate groups of px’s experience two different conditions of the experiment.

Question 3

Independent groups evaluation

Answer 3

Limitations
The px’s who occupy the different groups are not the same in terms of px variables. These differences may act as a confounding variable, reducing validity of the findings.

Strengths
Order effects aren’t a problem. Px’s less likely to guess the aims.

Question 4

Repeated measures

Answer 4

All px’s participate in all conditions of the experiment.

Question 5

Repeated measures evaluation

Answer 5

Strengths
Fewer px’s needed as one px does both levels of the IV so therefore less time spent recruiting them.

Limitations
Order effects is an issue. To deal with this researchers use counterbalancing.

Question 6

Matched pairs

Answer 6

Px’s are paired together on a variable or variables relevant to the experiment. (e.g. both 17 year old females). One member of the pair is assigned to condition A and the other is assigned to condition B. Attempt to control for confounding variables of px’s variables.

Question 7

Matched pairs evaluation

Answer 7

Strengths
Order effects and demand characteristics are less of a problem.

Limitations
Less economical as matching may be time consuming and expensive.