Experimental Design

Question 1

2 types of experimental design

Answer 1

Repeated measures and independent groups

Question 2

Repeated measures

Answer 2

Same ptps complete the 2 levels of the IV

Question 3

Independent groups

Answer 3

Different ptps compete the 2 level of IV

Question 4

How are ptps allocated in independent groups

Answer 4

Randomly to avoid researcher bias

Question 5

What type of data does independent groups produces

Answer 5

Unrelated data = the individual data points in one condition cannot be paired with any of the data points in the other conditions

Question 6

What type of data does repeated measures produce

Answer 6

Related data = each ptp score in one condition can be paired with a data point in the other condition

Question 7

How do u overcome order effect

Answer 7

Counter balance
- half ptps complete condition a first and b second and the other half ptps complete condition b first then a second

Question 8

Evaluation of independent groups

Answer 8

Strengths
- reduced demand characteristics = less likely to find out the aim
- no order effect = as ppt only take part in condition

Weaknesses
- Need double ptps compared to to RM for same mount of data
- time consuming
- ptp variables = between the conditions as the ptps only take part in one condition

Question 9

Evaluation of repeated measures

Answer 9

Strengths
- need half the number of pts compared IG for same amount of data
- no ptp variables as ptpt take part in both conditions

Weaknesses
- demand characteristic - likely to find out aim as they take part in both conditions
- order effect = ptps performance can worsen between conditions due to external factors like fatigue and practise

Question 10

Matched pairs design

Answer 10

• Different ppts complete in each of the 2 conditions of the experiment
  -ptps are first assessed and ranked on characteristics
• then top 2 ptp are randomly assigned to separate conditions

Question 11

What type of data does matched pairs design produce

Answer 11

Related data = each ptp score in one condition can be paired with data point in the other condition

Question 12

Evaluation of matched pairs design

Answer 12

Strengths
- reduced ptp variables - ptpt matched on relevant characteristics
- no order effect = ptp only take part in one condition

Weaknesses
- takes longer to set up
- time as many ptps as RM
- may be some ptp variables that influence the DV as ptps are similar not identical