Experimental design

Question 1

What are independant groups?

Answer 1

This is when one group does Condition A and a second group does Condition B. Participants should be randomly allocated to experimental groups.

Question 2

What are strengths of Independant groups?

Identify 2

Answer 2

1. No order effects
   Participants are only tested once so cant practice or become tired, this controls an important CV.
2. Will not guess the aim
   Participants only tested once so are unlikely to guess the research aims. Therefore behaviour may be more natural.

Question 3

What are the limitations of Independant groups?

2x

Answer 3

1. Participant variables
   The participants in the two groups are different, acting as EV/CV. May reduce the validity of the study/
2. Less economical
   Need twice as many participants as repeated measures for the same data, more time spent recruiting which is expensive

Question 4

What are Repeated measures?

Answer 4

Same participants take part in all conditions of an experiment. The order of conditions should be counterbalanced to avoid order effects.

Question 5

What are strengths of Repeated measures?

2x

Answer 5

1. Participant variables
   The person in both conditions has the same characteristics. this controls a important CV.
2. Fewer participants
   Half the number of participants is needed than in independant groups. Less time is spent recruiting participants.

Question 6

What are limitations of Repeated measures?

2x

Answer 6

1. Order effects are a problem
   Participants may do better or worse when doing a similar task twice. Also practice and fatigue effects. This reduces the validity of the results.
2. Participants can guess aims
   Participants may change their behaviour, this may reduce the validity of the results.

Question 7

What are Matched pairs?

Answer 7

Two groups of participants are used but they are also related to eachother by being paired on participant variables that matter for the experiment.

Question 8

What are strengths of Matched pairs?

Answer 8

1. Participant variables
   Participants matched on a variable that is relevant to the experiment. This controls participant varibales and enhances the validity of the results.
2. No order effects
   Participants are only tested once so no practice or fatigue effects, this enhances the validity of the results.

Question 9

What are limitations of matched pairs?

Answer 9

1. Matching is not perfect
   Matching is time-consuming and cant control all relevant variables. Cannot address all participant variables.
2. More participants
   Need twice as many participants as repeated measures for the same data. More time spent recruiting which is expensive.