Chi-Squared Ranking
Chi-Squared Test of Independence
The $\chi^2$ statistics measures the lack of independence between $f$ and $y$ and can be compared to $\chi^2$ with one degree of freedom
it’s zero when $f$ and $y$ are independent
$\chi^2$ measures how the results of an observation differs from the result expected according to the null hypothesis
- lower values indicate less dependency
- so for $\chi^2$ we want to take biggest values