MediumProbabilitypr-081

F Distribution PDF Value

Problem

F probability density with d1 numerator and d2 denominator degrees of freedom at x:

f(x) = sqrt((d1 * x)^d1 * d2^d2 / (d1 * x + d2)^(d1 + d2)) / (x * B(d1 / 2, d2 / 2)).

Return 0.0 for nonpositive parameters or x <= 0.

Hint

The Beta function in the denominator can be written with lgamma terms.

case 1

in: [1,1,1]

expected: 0.1591549430918952

case 2

in: [2,2,1]

expected: 0.25

case 3

in: [4,2,2]

expected: 0.12799999999999978

case 4

in: [1,1,0]

expected: 0

Starter codePython

import math


def f_pdf_value(d1, d2, x):
    # Your code here
    pass

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