bgeopdf

Beta-geometric probability distribution function.

This m-function returns the beta-geometric probability density function with parameters A and B at the values in X. Note: The density function is zero unless A and B are integers.

The Beta-geometric distribution is used to model the number of failures that will occur in a binomial proccess before the first success is observed and where the binomial p is itself a random variable taking a Beta(a,b) distribution.

It has been broadly applied in fecundability and manpower or contractual studies.

It has the probability density function:

B(a+x, b+1)
p(x) = --------------
B(a, b)

where B(a,b) is a beta function.

Syntax: function y = bgeopdf(x,a,b)

Inputs:
x - number of failures before the first success {0,1,2,...)
a - alpha parameter of Beta function (>0)
b - beta parameter of Beta function (>0)

Output:
y - beta-geometric probability value