Statistics
ANOVA
Outline
1. Situation: a categorical variable with I levels and a quantitative variable
2. Research question: is there a difference in the population means?
H0 : µ1 = µ2 = · · · = µI
Ha : not all of the µi are equal
3. Statistic; F – the bigger F is, the greater the evidence against H0 .
4. What does F measure?
F =
variation among means
variation within samples
5. The relationship between ANOVA and the two-sample t.
6. What to do if the null hypothesis appears to be false? From StatCrunch:
April 20, 2009