Fisher Exact Probability (Small Table)

Problem

Return the hypergeometric probability of the observed 2x2 table given its margins: C(a+b, a) * C(c+d, c) / C(n, a+c). Return 0.0 when the total is zero.

Hint

Use math.comb for the binomial coefficients.

Test cases

case 1

in: [1,9,9,1]

expected: 0.0005412544112234515

case 2

in: [5,0,0,5]

expected: 0.003968253968253968

case 3

in: [1,1,1,1]

expected: 0.6666666666666666

case 4

in: [0,0,0,0]

expected: 0

case 5

in: [2,3,4,5]

expected: 0.4195804195804196

Starter codePython

import math
def fisher_exact_probability(a, b, c, d):
    # Your code here
    pass

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