Two Class Posterior from Likelihoods

Problem

For two classes with prior P(C1) = prior and likelihoods l1, l2, the posteriors are proportional to [prior l1, (1 - prior) l2] normalized to sum to one.

Given the prior and the two likelihoods, return [P(C1 | x), P(C2 | x)].

Hint

Multiply prior by likelihood, then normalize.

Test cases

case 1

in: [0.5,0.8,0.2]

expected: [0.8,0.2]

case 2

in: [0.3,0.9,0.1]

expected: [0.7941176470588235,0.20588235294117643]

case 3

in: [0.5,0.5,0.5]

expected: [0.5,0.5]

Starter codePython

def two_class_posterior_from_likelihoods(prior, l1, l2):
    # Your code here
    pass

3 test cases · run your code against them in the editor