the experimental design

Question 1

What is the experimental design?

Answer 1

The way in which ppts are used in experiments (how they’re arranged)

Question 2

What are the 3 types of experimental design?

Answer 2

1. Independent groups - 2 separate groups experience 2 different conditions.
2. Repeated measures - ppts experience both conditions and the two sets of data are compared e.g. ‘before’ and ‘after’
3. Matched pairs - ppts are paired together usually on a variable or variables relevant to the experiment e.g. matched on IQ

Question 3

Independent groups evaluation

Answer 3

• order effects are not a problem
• ppts in the different groups aren’t the same - differences between conditions may be due to individual difference not the effect of the IV - researchers may use random allocation to stop this
• needs twice as many ppts

Question 4

Repeated measures evaluation

Answer 4

• ppt variables are controlled and fewer ppts are needed
• each ppts has to at least two tasks and the order may be significant - the first condition could have a continuing effect - order effects may arise - boredom and fatigue could lead to a worse performance in the second condition

Question 5

Matched pairs evaluation

Answer 5

• order effects and demand characteristics are less of a problem
• ppts can’t be matched easily - matching could be time consuming and expensive especially if a pre-test is required