module 9

Question 1

What is the key advantage of repeated-measures (within-subjects) designs?

Answer 1

A: They allow us to account for individual differences, reducing error variance and increasing statistical power.

Question 2

Why is repeated-measures ANOVA more powerful than between-groups design?

Answer 2

A: Because it removes variance due to individual differences, resulting in a smaller error term.

Question 3

What are the three sources of variance in a repeated-measures factorial ANOVA?

Answer 3

A: Main effect 1, Main effect 2, and Interaction (plus associated error terms and individual differences).

Question 4

What are estimated marginal means used for in SPSS ANOVA output?

Answer 4

A: To visualize and interpret main effects and interactions.

Question 5

What are simple effects analyses used for in factorial ANOVA?

Answer 5

A: To examine specific effects within one level of a factor (e.g., how treatment affects mood at each time point).