RM - Experimental Designs

Question 1

Strength of Independent Group

Answer 1

No order effects → ppts only take part in 1 condition→won’t get bored/ better/ fatigued by/at task/ no lasting effect from C1 to C2 (context) → unlike repeated measures, ppts take part in both/all

Question 2

Weakness of Independent Group

Answer 2

Individual differences may affect DV → separate groups for each condition → e.g some ppts may have better memory not suitable in memory study (change to fit study - context) → ↓ in val → unlike repeated measures same group of ppts for each condition, reduces effect of individual differences

Question 3

Strength of Repeated Measures Design:

Answer 3

Individual differences between ppts in each condition removed → same group of ppts for each condition (context) → researcher can make sure any changes in DV are due to IV and not other variables, ↑ in val → unlike IGD, uses different group of ppts for each condition, so may be affected by individual differences.

Question 4

Weakness of Repeated Measures Design:

Answer 4

Order effects → ppts take part in both condition→ may get perform worse (bored/ fatigued) or better at task/ lasting effect from C1 to C2 (context), ↓ in val → unlike IGD, ppts take part in 1 condition so can’t be susceptible to order effects

Question 5

Matched Pairs Design Definition:

Answer 5

Ppts are tested on a characteristic (important and relevant to DV), using an appropriate test. Match 2 ppts with same score. Randomly allocate each member of the pair across the 2 conditions

Question 6

How to conduct a matched pairs design?

Answer 6

Choose variable to match ppts on. Test ppt on this variable before study. Match ppts with same scores. Randomly allocate each member of the pair to one condition.

Question 7

Strength of MP Design (regarding individual diffs)

Answer 7

Reduces individual differences → ppts matched on variables important to research (context)→ researcher can make sure any changes in DV are due to IV and not other variables → ↑ in val

Question 8

Strength of MP Design (regarding order effects)

Answer 8

No order effects → only take part in 1 condition → won’t get bored/ fatigued/ better by next condition (context) → unlike RM, ppts take part in all conditions, could have order effects

Question 9

Weakness of MP Design (regarding individual diffs)

Answer 9

Individual differences not fully eliminated → psychologists can match ppts on variables important to research but not all variables (context) → questions validity of MP design → unlike RM, each condition has same set of ppt, therefore individual differences fully eliminated

Question 10

Control for Individual Differences:

Answer 10

RANDOM ALLOCATION
1. Write the names of the ppts on equal sized pieces of paper.
2. Put the paper in a hat.
3. Then randomly pick out ppts’ names and place half in condition 1 and the other half in condition 2 (context - numbers, names of conditions)

Question 12

Control for Order Effects:

Answer 12

COUNTERBALANCING (ABBA)
1. Half the ppts complete C1 then C2 (context).
2. The other half complete C2 then C1 (context)
3. Order effects are balanced across the 2 conditions