StatKit could use some different effect size measures. This issue serves to collect a list of relevant ones to be implemented. Candidates: - [R<sup>2</sup>](https://en.wikipedia.org/wiki/Coefficient_of_determination) - [Adjusted R<sup>2</sup>](https://en.wikipedia.org/wiki/Coefficient_of_determination#Adjusted_R2) - [Cohen's F<sup>2</sup>](https://en.wikipedia.org/wiki/Effect_size#Cohen's_f2) - [Cohen's d](https://en.wikipedia.org/wiki/Effect_size#Cohen's_d) - [Cohen's Omega](https://en.wikipedia.org/wiki/Effect_size#Cohen's_omega_(ω))