
A confusion matrix C is such that C(i, j) is equal to the number
of observations known to be in group i but predicted to be in group j.


If the classifier is nice, the diagonal is high because there are
true positives

Genderize confusion matrix:

      M   F   U  
M  [[ 5,  0,  0 ]
F   [ 0,  1,  0 ]]
