Hi, I'm reading: http://scikit-learn.org/stable/modules/generated/sklearn.preprocessing.StandardScaler.html

(1) It says "Standardize features by removing the mean and scaling to unit variance" but a formula should be stated to make it explicit. Not everyone will understand what it means to say "removing the mean and scaling to unit variance".

(2) The documentation for scale_ doesn't say how it is defined. The documentation should say how it is defined.

The documentation for the var_ says "Used to compute scale_" but it doesn't say how.

I gather from looking at examples that scale_ = sqrt(var_) but the documentation should say that explicitly, preferably under the heading for scale_.