Lecture 11

Question 1

within-subjects designs

Answer 1

each participant is exposed to all the levels of the IV

-repeated measures design

Question 2

advantages of a within subjects designs

Answer 2

• participant variables less likely to become confounding
• fewer participants required
• less variability means statistical advantage
• no control group issues

Question 3

threats to internal validity for within subjects designs

Answer 3

MRS SMITH: M, R, I, T, H

• maturation
• regression to the mean
• instrumentation
• history

Question 4

time-related effects

Answer 4

1. testing/practice effects (T): subjects perform better due to practice with testing procedure
2. carryover/ contrast effects: after effects of one treatment remain/influence perception when moving on to another treatment
3. fatigue effects: participants perform differently at the end of an experiment

Question 5

disadvantages of within subjects designs

Answer 5

• time related and order related threats to internal validity
• MRITH (MRS SMITH)
• impossible for some research questions

Question 6

counterbalancing

Answer 6

• order of levels of IV is varied to reduce order effects

- removes the confound