# Documentation/Calc Functions/GAMMAINV

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GAMMAINV

## Category:

Statistical Analysis

## Summary:

Calculates the inverse of the gamma cumulative distribution function. This function allows you to search for variables with a different distribution.

## Syntax:

GAMMAINV(Number; Alpha; Beta)

## Returns:

Returns a non-negative real number is the inverse of the gamma cumulative distribution such that if p = GAMMA.DIST(n;a;b;TRUE()) then GAMMAINV(p;a;b) = n.

## Arguments:

Number is a real number or a reference to the cell containing that number which is the probability value for which the inverse gamma distribution is to be calculated. It ranges from 0(inclusive) to 1(exclusive), i.e. [0,1).

Alpha is a real number or a reference to the cell containing that number which is the alpha (shape) parameter for the gamma distribution.

Beta is a real number or a reference to the cell containing that number which is the beta (rate) parameter for the gamma distribution.

• If Number is less than zero or greater than or equal to 1, then the function returns an error value.
• If either of Alpha or Beta is negative or zero then the function returns an error value.

## Additional details:

For more details on the inverse gamma distribution, visit Wikipedia

## Examples:

Formula Description Returns
=GAMMAINV(0.4,3.4,4.5) The function calculates the cumulative distribution function for the gamma distribution with Number as 0.4, Alpha as 3.4 and Beta as 4.5 . This can be alternatively considered as =GAMMADIST(11.9431323164629;3.4;4.5;TRUE()) gives 0.4. 11.9431323164629
=GAMMAINV(0,3.4,4.5) The function calculates the cumulative distribution function for the gamma distribution with Number as 0, Alpha as 3.4 and Beta as 4.5 . 0
=GAMMAINV(1,3.4,4.5) The function returns an error since the Number is equal to 1. Err:502
=GAMMAINV(-4,3.4,4.5) The function returns an error since the Number is negative. Err:502

GAMMAINV