ANOVA (between groups)

Question 1

Why not use multiple t-tests?

Answer 1

Multiple t-tests increases type I error rate

Question 2

What is ANOVA

Answer 2

-Extension of t-test for 3+ groups
-Compares means across multiple groups while maintaining statistical power

Question 3

Assumptions of ANOVA

Answer 3

-Independent and random sampling
-Approx. normal distribution
-Roughly equal group sizes
-Equal variance across groups

Question 4

Logic behind ANOVA

Answer 4

-ANOVA compares explained variance (between groups) and unexplained variance (within groups)
-If explained > unexplained -> significance effect

Question 5

F-Ratio

Answer 5

Larger F = more likely groups differ

Question 6

Limitation of ANOVA

Answer 6

Doesn’t specify which groups differ

Question 7

Pairwise comparison

Answer 7

-Planned comparison
-Post-hoc tests
-Bonferroni correction

Question 8

Planned comparisons

Answer 8

Hypothesis-driven

Question 9

Post-hoc tests

Answer 9

-Data driven
-Only conduct if main effect is significant

Question 10

Bonferroni correction

Answer 10

Alpha/number of tests

Question 11

One way ANOVA

Answer 11

One IV

Question 12

2-way or multi-factor ANOVA

Answer 12

More IVs

Question 13

MANOVA

Answer 13

Multiple DV

Question 14

ANCOVA

Answer 14

Controls for continuous covariates

Question 15

SPSS procedure for ANOVA

Answer 15

-Analyse > compare means >one-way ANOVA
-Analyse > general linear model > univariate
-Define fixed factor (IV), DV and run post-hoc tests