Ee = entropy of the cut-point E1 = entropy to the left of the cut-point E2 = entropy to the right of the cut-point k = total number of classes i = a practical class
pleft = number of instances to the left of cut-point / total number of instances, N pright = number of instances to the right of cut-point / total number of instances, N pi,left = num of instances of class i to the left of cut- point / number of instances to the left of cut-point pi,right = {num of instances of class i to the right of cut-point } / { number of instances to the right of cut- point}