Beta Second Moment

Problem

For a Beta(a, b) distribution, E[X^2] = a (a + 1) / ((a + b)(a + b + 1)).

Given a and b, return the second moment.

Hint

Shift the first parameter in both the numerator and the total.

case 1

in: [2,2]

expected: 0.3

case 2

in: [1,1]

expected: 0.3333333333333333

case 3

in: [5,2]

expected: 0.5357142857142857

Starter codePython

def beta_second_moment(a, b):
    # Your code here
    pass

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