Experimental Designs

Question 1

what are the types of experimental designs?

Answer 1

• independent groups
• repeated measures
• matched pairs

Question 2

what is independent groups design?

Answer 2

• two separate groups of ppts experience two different conditions
• two levels of independent variable, one group is assigned to one IV
• performance of 2 groups would be compared

Question 3

what is a strength of independent groups design?

Answer 3

• no order effects
• less demand characteristics = less likely to guess the aims
• less economical that repeated measures, each ppt contributes a single result only

Question 4

what is a weakness of independent groups design?

Answer 4

• difference on the DV may be due in participant variables
• differences may act as a confounding variable , reducing validity of finding
• more time consuming = more ppts needed compared to repeated measures

Question 5

how do we overcome the problem of participant variables in independent groups design?

Answer 5

• use random allocation, e.g using a hat

Question 6

what is repeated measures design?

Answer 6

• all participants experience both conditions of the experiment

Question 7

what are the weaknesses of repeated measures design?

Answer 7

• order effects, e.g. boredom which could deteriorate performance in the second task
• demand characteristics

Question 8

what are strengths of repeated measures design?

Answer 8

• participant variables are controlled
• fewer participants are needed