Experimental Design

Question 1

Acronym for remebering experimental design:

Answer 1

I Get Really Mad Matching Penguins

IG - Independent groups

RM - Repeated Measures

MP - Matched Pairs

Question 2

What are the three main experimental designs?

Answer 2

• Repeated measures
• Independent groups
• Matched pairs

Question 3

What is an indepdent group?

Answer 3

One group does condition A and second group do condition B

Partipants are randomly allocated to different groups which represent different conditions

Each group only does one of the condition of the IV

Question 4

Strength of independent groups

Answer 4

• No order effects: Particpant only tested once so can’t practice or become bored -control important CV
• Will not guess aim: Particpants only tested once so unlikely to guess the research aims thereofe behaviour is more natural

Question 5

Weakness of indepdent groups

Answer 5

• Particpant variables: The particpants in two groups are different actinf EV/CV so reduce validity of study
• More particpants: Need twice as many particpants as repeated measures for same data as spent more time recuting is expensive

Question 6

What is repeated measures design?

Answer 6

Same particpants used in both/all condtions

The order of conditions should be counterbalanced to avoid order effects

Question 7

Strength of repeated measure design:

Answer 7

• Particpant variables: Person both conditions has same characteristic so controls important CV
• Fewer particpants: Half of the number of particpants needed in indepdent groups as less time recuiting participants

Question 8

Weakness of repeated measure group:

Answer 8

• Order effects are a problem: Particpants may do better or worse doing similar task twice
• Reduce validity of results
• Partipants may guess aims : Particpants may change their behaviour so reduce validity of results

Question 9

What is matched pairs?

Answer 9

Pais of particpants are closely matched and then randomly allocated to one of the experimental condtions

Question 10

Strengths of matched pairs

Answer 10

• Particpant variables: They are matched on variable relevent so enhances validity of results
• No order effects: Particpants only tested once so no practice or fatigue as enhances validity of results

Question 11

Weakness of matched pairs

Answer 11

• Matching is not perfect : It is time-consuming so can’t control all relevent variables so not address particpant variables
• More particpants: Need twice as many particpants as repeated measure for same data, more time recuiting which is expensive