controls: experimental design

Question 1

Problem: independent groups design

Answer 1

• individual differences possible issue
• different ppt in each condition
• in one condition ppt may have particular trait
• makes them perform better at DV (CONTEXT)
• meaning wasn’t IV affect DV
• lowers internal validity

Question 2

Control: random allocation - why

Answer 2

• ensures each ppt has same chance
• being in one condition as any other
• unlikely all ppts in one condition share characteristic
• to help them perform better at DV

Question 3

Control: random allocation - how

Answer 3

1. write names ppts on equal sized pieces of paper
2. put paper into hat
3. randomly pick out ppts half in condition 1 other hald condition 2

Question 4

Problem: repeated measures design

Answer 4

• order effects possible issue
• ppt take part in all conditions
• may perform better 2nd condition - practise
• may perform worse 2nd condition - boredom/fatigue
• may have lasting effects one condition to next
• (CONTEXT)

Question 5

Control: counterbalancing - why

Answer 5

• control and reduce order effects

Question 6

Control: counterbalancing - how

Answer 6

1. half ppts complete condition A then condition B (CONTEXT)
2. other half complete condition B then condition A
3. order effects balanced/ distributed across both conditions

(ABBA)