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WorksheetFunction.Gamma_Dist Method (Excel)

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.

Return Value

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: Ff839080.awfgmdi1_ZA06051146(en-us,office.14).gifThe standard gamma probability density function is: Ff839080.awfgmdi2_ZA06051147(en-us,office.14).gif

  • When alpha = 1, GAMMA_DIST returns the exponential distribution with: Ff839080.awfgmdi3_ZA06051148(en-us,office.14).gif

  • 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.

See Also

Concepts

WorksheetFunction Object

WorksheetFunction Object Members