# WorksheetFunction.Gamma_Inv method (Excel)

Returns the inverse of the gamma cumulative distribution. If p = GAMMA_DIST(x,...), then GAMMA_INV(p,...) = x.

## Syntax

expression. `Gamma_Inv`( `_Arg1_` , `_Arg2_` , `_Arg3_` )

expression A variable that represents a 'WorksheetFunction' object.

## Parameters

Name Required/Optional Data type Description
Arg1 Required Double Probability - the probability associated with the gamma distribution.
Arg2 Required Double Alpha - a parameter to the distribution.
Arg3 Required Double Beta - a parameter to the distribution. If beta = 1, GAMMA_INV returns the standard gamma distribution.

Double

## Remarks

You can use this function to study a variable whose distribution may be skewed:

• If any argument is text, GAMMA_INV returns the #VALUE! error value.

• If probability < 0 or probability > 1, GAMMA_INV returns the #NUM! error value.

• If alpha ? 0 or if beta ? 0, GAMMA_INV returns the #NUM! error value.

Given a value for probability, GAMMA_INV seeks that value x such that GAMMA_DIST(x, alpha, beta, TRUE) = probability. Thus, precision of GAMMA_INV depends on precision of GAMMA_DIST. GAMMA_INV uses an iterative search technique. If the search has not converged after 100 iterations, the function returns the #N/A error value.