MediumProbabilitypr-086

PGF of Geometric

Problem

Probability generating function of the geometric distribution for the number of trials until the first success:

G(z) = p * z / (1 - (1 - p) * z).

Return 0.0 when the denominator is 0.

Hint

Sum p * ((1 - p) * z)^(k - 1) * z over k >= 1.

case 1

in: [0.5,1]

expected: 1

case 2

in: [0.5,0]

expected: 0

case 3

in: [0.2,0.5]

expected: 0.16666666666666669

case 4

in: [0.5,2]

expected: 0

Starter codePython

def pgf_geometric(p, z):
    # Your code here
    pass

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