Comparing Analysis of Variance ANOVA

Question 1

Family wise error

Answer 1

1 - 0.95^n

Question 2

Why is an omnibus test superior?

Answer 2

• t-tests have limitations (can only compare 2 means, only one independent variable)
• ANOVA compares several means
• can be used when you have manipulated more than one independent variable
• extension of regression

Question 3

ANOVA is an omnibus test

Answer 3

• it tests for an overall difference between groups
• it tells us that the group means are different
• it doesn’t tell us exactly which means differ

Question 4

Post-hoc tests

Answer 4

• tells you whether you have an overall difference between your groups ans which specific groups differed
• no hypothesis
• compare all pairs of means

Question 5

Interactions of ANOVA

Answer 5

interaction is present if the effect of one factor

depends on the level of the other factor

Question 6

Assumptions of ANOVA

Answer 6

• independence of cases – this is an assumption of the model that simplifies the statistical analysis.
• normality – the distributions of the residuals are normal.
• equality (or “homogeneity”)