
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:

      F   M   U  
F  [[ 6,  0,  0 ]
M   [ 1,  28,  0 ]]
