Experimental Design

Question 1

What are Independent Groups?

Answer 1

Diff PPTS used for each condition

If 2 IV levels 1 group in control, other experiment

Random allocation= equal chance of being in each group

Question 2

What are repeated measures?

Answer 2

Same PPTS in both conditions

Each condition has the same group

Question 3

What are matched pairs?

Answer 3

PPTS put in pairs by matching in key variables (age)

One member of each pair is placed in 2 diff conditions.

Question 4

Give Strengths and weaknesses of INDEPENDENT GROUPS

Answer 4

+ Order effects avoided- only in one so cannot get bored.

+ Dmd charas avoided- only in one so less likely to guess aim.

• More PPTS needed
• PPTS variables: may be due to characteristics not DV manipulation

Question 5

Give strengths and weaknesses of REPEATED MEASURES

Answer 5

+ fewer PPTS needed

+ PPTS variables controlled as no indiv diffs as the same people take part

• Order effects- some get worse in conditions + get bored
• Dmd charas more likely to work out aim as in both. May alter behavior

Question 6

Give strengths and weaknesses of MATCHED PAIRS

Answer 6

+ PPTS variables reduced as similar

+ Order effects avoided as only in 1 condition so not bored

+ dmd charas reduced, in 1 so less likely to guess aim

• time consuming
• expensive to match individuals
• idiv differences occur as they can never be exact= PPTS variables