# WorksheetFunction.Gamma_Dist Method (Excel)

Office 2010

Returns the gamma distribution. You can use this function to study variables that may have a skewed distribution. The gamma distribution is commonly used in queuing analysis.

## Version Information

Version Added: Excel 2010

## Syntax

expression .Gamma_Dist(Arg1, Arg2, Arg3, Arg4)

expression A variable that represents a WorksheetFunction object.

### Parameters

Name

Required/Optional

Data Type

Description

Arg1

Required

Double

X - the value at which you want to evaluate the distribution.

Arg2

Required

Double

Alpha - a parameter to the distribution.

Arg3

Required

Double

Beta - a parameter to the distribution. If beta = 1, GAMMA_DIST returns the standard gamma distribution.

Arg4

Required

Boolean

Cumulative - a logical value that determines the form of the function. If cumulative is TRUE, GAMMA_DIST returns the cumulative distribution function; if FALSE, it returns the probability density function.

Double

## Remarks

• If x, alpha, or beta is nonnumeric, GAMMA_DIST returns the #VALUE! error value.

• If x < 0, GAMMA_DIST returns the #NUM! error value.

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

• The equation for the gamma probability density function is: The standard gamma probability density function is:

• When alpha = 1, GAMMA_DIST returns the exponential distribution with:

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

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