ANOVA II Exam questions with solutions
Explain what an omnibus test is, and list the effects in a 2-way ANOVA that can be
categorized as omnibus tests - answersAny test resulting from the preliminary
partitioning of variance in ANOVA
Three effects: main effect IV1, main effect IV2 and interaction effect
Identify the circumstances in which follow-up tests are required in 2-way factorial
ANOVA - answersIf there is a difference between the means
When following up main effects in a 2-way ANOVA:
1) Identify the research question (and hypothesis) being tested
2) Identify the type of means that are compared
3) Identify the type of statistical test (e.g. F, t, z) that is used
4) Explain how you would determine the number of follow-up tests that are needed
5) Explain what a significant main effect comparison tells you - answers1) What
direction is the effect in
2) Marginal means
3) T test (protected) or linear contrasts
4) Only if the main effect is significant
5) there is a difference in the marginal means (somewhere)
When following up a significant two-way interaction in a 2-way ANOVA:
1) Identify the two (possible) steps in the analyses
2) Identify the types of means that are being compared. - answers1) simple effects and
simple comparisons
2) cell means
When testing simple effects in a 2-way ANOVA:
1) Identify the research question (and hypothesis) being tested
2) Identify the type of statistical test (e.g. F, t, z) that is used
3) Identify the error term that is used
4) Identify how degrees of freedom are calculated for SSeffect / treatment and SSerror
5) Explain how you would determine the maximum number of simple effects that could
be tested for a factor
6) Explain what a significant simple effect tells you - answers