R Squared Coefficient of Determination - Machine Learning Concept

*coefficient of determination*](http://stattrek.com/statistics/dictionary.aspx?definition=coefficient_of_determination)

R^2
R²

coefficient of determination
useful statistics for regression analysis
measures how good the model makes prediction.


R^2 range {0, 1}
can be negative, arbitrarily worse
percentage of square correlection between predicted and actual values of target variable

indicates what percentage of the target variable, using this model, can be explained by the **features**.


r2_score from sklearn.metrics