Wilks Lambda Lite

Problem

Return Wilks' lambda det(E)/det(E + H) for 2x2 within-group (E) and hypothesis (H) SSCP matrices. Return 0.0 when the shapes are not 2x2 or det(E + H) is zero.

Hint

Lambda is 1 when the effect adds nothing and approaches 0 for strong effects.

Test cases

case 1

in: [[[4,1],[1,3]],[[2,0.5],[0.5,1]]]

expected: 0.5057471264367817

case 2

in: [[[1,0],[0,1]],[[1,0],[0,1]]]

expected: 0.25

case 3

in: [[[2,1],[1,2]],[[0,0],[0,0]]]

expected: 1

case 4

in: [[[1,1],[1,1]],[[2,0],[0,2]]]

expected: 0

case 5

in: [[[3,0.5],[0.5,2]],[[1,0.2],[0.2,1]]]

expected: 0.49956559513466553

Starter codePython

def wilks_lambda(sscp_e, sscp_h):
    # Your code here
    pass

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