ANOVA

Practicing Statistics Interview Questions in R

Zuzanna Chmielewska

Actuary

Hypotheses

$$ H_0: \mu_1 = \mu_2 = ... = \mu_n$$

$$ H_1: \exists_{(i,j)} \mu_i \ne \mu_j $$

Hypotheses

$$H_0: \mu_1 = \mu_2 = \mu_3 $$

Hypotheses

Two-sample t-test: $$ H_0: \mu_1 = \mu_2 $$

Hypotheses

$$ H_0: \mu_1 = \mu_2 = ... = \mu_n$$

Why not multiple t-tests?

Why not multiple t-tests?

Why not multiple t-tests?

Why not multiple t-tests?

Why not multiple t-tests?

Assumptions

• independence of cases
• normal distributions
• homogeneity of variances

ANOVA in R

oneway.test(value ~ group, data, var.equal = TRUE)

Box plot

Box plot

Box plot

Box plot

Box plot

Box plot

Box plot

Summary

• hypotheses of ANOVA
• type I and II errors
• assumptions of ANOVA
• oneway.test() in R
• box plot

Let's practice!

Practicing Statistics Interview Questions in R