GAMMADIST

Syntax:

GAMMADIST ( x , alpha , beta , cumulative-flag )

Description: Computes the gamma distribution.

Mathematical Formula:

The equation for the gamma probability density function is:

The standard gamma probability density function is:

When alpha = 1, GAMMADIST returns the exponential distribution with:

For a positive integer n, when alpha = n/2, beta = 2, and cumulative = TRUE, GAMMADIST returns (1-CHIDIST(x)) with n degrees of freedom.

When alpha is a positive integer, GAMMADIST is also known as the Erlang distribution.

Arguments:

Name	Type	Description
x	number	The value at which the distribution is to be evaluated.
alpha	number	A parameter of the distribution.
beta	number	A parameter of the distribution. If beta = 1, `GAMMADIST` returns the standard gamma distribution.
cumulative-flag	logical	Determines the form of the function. If `TRUE`, `GAMMADIST` returns the cumulative distribution function; if `FALSE`, it returns the probability density function.

Return Type and Value: number – The gamma distribution.

However, if

example: