Moderated Mediation Index

Problem

Compute the index of moderated mediation: (a_high - a_low) * b, where a_low and a_high are the treatment-to-mediator effects at two moderator levels and b is the mediator-to-outcome effect.

Hint

A nonzero index means the indirect effect depends on the moderator.

Test cases

case 1

in: [0.3,0.5,0.8]

expected: 0.16000000000000003

case 2

in: [0.5,0.2,0.4]

expected: -0.12

case 3

in: [0.4,0.4,1]

expected: 0

Starter codePython

def moderated_mediation_index(a_low, a_high, b):
    # Your code here
    pass

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