Chi-Square Distance

Problem

Compute the chi-square distance between two distributions:

chi2 = sum((p_i - q_i)^2 / q_i)

Assume q_i > 0 for every outcome.

Hint

The chi-square distance weights differences by the reference probability 1 / q_i.

case 1

in: [[0.5,0.5],[0.25,0.75]]

expected: 0.3333333333333333

case 2

in: [[0.5,0.5],[0.5,0.5]]

expected: 0

case 3

in: [[0.25,0.75],[0.5,0.5]]

expected: 0.25

case 4

in: [[0.2,0.3,0.5],[0.25,0.25,0.5]]

expected: 0.01999999999999999

Starter codePython

def chi_square_distance(p, q):
    # Your code here
    pass

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