mixed ANOVA

Question 1

between subjects assumptions

Answer 1

• normal distribution of scores
• homogeneity of variances (at each combination of levels of factors A and B)
• independent of observations

Question 2

within subjects assumptions

Answer 2

• sphericity (tested only for the within subject main effect - use mauchly’s test and if sphericity is violated, the same 𝜀 is used for both within subject effects)

Question 3

violations of assumptions

Answer 3

sphericity:
- increases type 1 errors for within subject effects

homogeneity of variance:
- depend on equality of within group sample sizes
- type 1 error rate >⍺ when smaller groups have higher variability (increased rate of false positives) and tyle 1 error rate <⍺ when smaller groups have lower variability (lower power to detect effects)