Probability estimaton test

Tests whether the given classifier lives up to its probability estimates. Counts the real prediction correctness and compares with the predicted probability. For example, we expect that in 2-class classification among entries with predicted probability=0.6 around 6/10 should be class 1 and 4/10 class 0. Of course, this is not a sufficient condition for correctness of the probability assessment, but a necessary one.