VIF for Two Variables

Problem

Compute the variance inflation factor for two variables: 1 / (1 - r^2) where r is their Pearson correlation.

Return 0.0 if a variance is 0 or |r| = 1.

Hint

VIF explodes as the two predictors become collinear.

case 1

in: [[1,2,3],[2,4,6]]

expected: 0

case 2

in: [[1,2,3,4],[1,3,2,5]]

expected: 3.240740740740738

case 3

in: [[1,1,1],[1,2,3]]

expected: 0

case 4

in: [[],[]]

expected: 0

Starter codePython

def vif_two_variables(x1, x2):
    # Your code here
    pass

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