GAMMAINV

Syntax:

GAMMAINV ( probability , alpha , beta )

Description: Computes the inverse of the gamma distribution. Given a value for probability, GAMMAINV seeks that value x such that GAMMADIST(x, alpha, beta, TRUE) = probability. Thus, the precision of GAMMAINV depends on the precision of GAMMADIST. GAMMAINV uses an iterative search technique.

Arguments:

Name

Type

Description

probability

number

The probability associated with the gamma distribution.

alpha

number

A parameter of the distribution.

beta

number

A parameter of the distribution. If beta = 1, GAMMAINV returns the standard gamma distribution.

Return Type and Value: number – The inverse of the gamma distribution.

However, if

  • probability < 0 or probability > 1, #NUM! is returned.

  • alpha ≤ 0 or beta ≤ 0, #NUM! is returned.

  • The search has not converged after some implementation-defined number of iterations, #N/A is returned.

example: