Experimental design

Question 1

Repeated measures

Answer 1

• all participants recieve all levels of the IV
  e.g each participant does a task with the tv on and then a weak later they do it without the tv on
• compare DV at the end of two tests

Question 2

Independent groups

Answer 2

• participants are placed in seperate groups and does one level of the IV
  e.g one group does a task without Tv and the other group does it with the TV

Question 3

Matched pairs

Answer 3

• a compromise is to use two groups of participants but match participants on key characteristics believed to affect performance on the DV
• one member of the pair is allocated to different groups
  -characteristics have to be relevant

Question 4

Repeated measures disadvantages

Answer 4

• order of the conditions may affect performance
  e.g participants may do better on second test than first because of practice effect/boredom effect or being anxious
• may do worse as they have got the grasp of the experiment

How to deal with it :
use two different tests to reduce practice effect
- can use a cover story

Question 5

Independent groups disadvantages

Answer 5

• researcher cannot control the effect of participant variables e.g participants in group A might happen to have better memory than those in group B

How to fix this:
Randomly allocate participants to distribute variables evenly
- can draw names out of a hat etc

Question 6

Matched pairs disadvantages

Answer 6

• time consuming to patch participants on key variables
• hard to know what other variables can influence even if matched with key variables

How to fix: conduct a pilot study to identify possible problems
- restrict numbers of variables to match