Summing Up Probabilities

Summing Up Probabilities

Let's have 30 elements of class A, 20 of B and 10 of C.

If in a generated tree an element under classification ends up in a leaf that have the following numbers of elements: (A: 10, B: 10, C: 10) then the probability for all the classes in the leaf will be calculated as follow:

Ap = 10/30 = 0.(3)

Bp = 10/20 = 0.5

Cp = 10/10 = 1

S = Ap + Bp + Cp = 1.8(3)

Ap /= S = 0.(18)

Bp /= S = 0.(27)

Cp /= S = 0.(55)

If it was the binary voting system the C class would be selected from this tree and the most voted class would be set for the element under classification.

In this scenario, we sum up the selected probabilities of all the trees and the class with the highest score will be set.