experimental designs

Question 1

experimental designs definition

Answer 1

how participants are allocated to the conditions of an experiment

Question 2

independent groups

Answer 2

participants are allocated to different groups where each group represents one experimental condition

Question 3

matched pairs

Answer 3

pairs of participants are first matched on some variable that may affect the DV. Then one member of the pair is randomly assigned to condition A and the other to B

Question 4

repeated measures

Answer 4

all participants take part in all conditions of the experiment

Question 5

random allocation

Answer 5

an attempt to control participant variables in an independent groups design which ensures that each participant has the same chance of being in one condition as any other

Question 6

counterbalancing

Answer 6

an attempt to control order effects in a repeated measures design. half the participants experience the conditions in one order, and the other half in the opposite order

Question 7

strengths of independent groups

Answer 7

• order effects arent a problem as participants only take part in 1 condition
• demand characteristics less likely
• standardised (can use the same materials in both groups)

Question 8

weaknesses of independent groups

Answer 8

• participant variables in each of the different groups arent the same so participant variables could be a CV
• less economical as each participant can only contribute a single result so twice the amount of participants would be needed to produce the equivalent data of a repeated measures result

Question 9

how to overcome weakness of independent groups

Answer 9

• random allocation overcomes participant variables. (each participant has an equal chance of ending up in each condition)

Question 10

strengths of matched pairs

Answer 10

• order effects arent a problem
• demand characteristics less likely
• can use the same materials in both groups (standardised)
• some participant variables are controlled

Question 11

weaknesses of matched pairs

Answer 11

• participant variables may still be a problem as we are unlikely to match all participants based on all variables
• matching is time consuming and less economical
• more participants needed than for repeated measures

Question 12

how to overcome weaknesses of matched pairs

Answer 12

• match them on fewer variables (computer)
• pilot study to work out the most important participant variables and match them on those

Question 13

strengths of repeated measures

Answer 13

• participant variables not a problem as same people are in each condition
• fewer participants needed so less time consuming and more economical

Question 14

weaknesses of repeated measures

Answer 14

• order effects
• cant use the same materials in both groups (not standardised)
• demand characteristics likely as participants take part in all conditions

Question 15

how to overcome weaknesses of repeated measures

Answer 15

• time gap between conditions
• counterbalancing
• use different materials but equivalent materials