power_anova eta parameter is actually eta-squared

[Riley16]

pingouin/pingouin/power.py

Line 373 in 8825a21

def power_anova(eta=None, k=None, n=None, power=None, alpha=0.05):

The eta parameter in power_anova (and potentially functions which I haven't checked) is actually eta-squared, but the documentation doesn't make this clear enough:
eta : float
ANOVA effect size (eta-square = 𝜂2)

The documentation as is could be taken to imply that the parameter entered by the user is eta, while the actual effect size eta-squared is the square of the user-entered parameter eta. I'd suggest making the docstring more explicit (saying something like "Actually equal to eta-squared") or renaming the parameter to eta2 or eta_squared.

[raphaelvallat]

Hi @Riley16,

(This is indirectly related to #254)

Thanks for catching this. I think that renaming the parameter to eta_squared is probably the best option to avoid any confusion! Please feel free to submit a PR. Otherwise I'll just fix this in the next release of Pingouin.

Thanks,
Raphael