# ML Wiki

## Pairwise t-test

• we have $n$ groups, $n > 2$
• we conduct a series of Two-Sample t-tests to find out which groups are different
• e.g. in post-ANOVA analysis

### Controlling Family-Wise Error Rate

It's important to modify $\alpha$ to avoid Type I Errors

• when we run many tests, it's inevitable that we make them just by chance

E.g. use Bonferroni Correction

• use modified confidence level $\alpha^* = \alpha \cdot \cfrac{1}{K}$
• where for $k$ groups $K= \cfrac{k \cdot (k - 1)}{2}$