Purpose

Return value

Syntax

=GAMMADIST(x,alpha,beta,cumulative)
  • x - The value at which to evaluate the distribution.
  • alpha - The shape parameter of the distribution.
  • beta - The scale parameter of the distribution.
  • cumulative - A logical value that determines the form of the function. If TRUE, returns the cumulative distribution function; if FALSE, returns the probability density function.

Using the GAMMADIST function

The GAMMADIST function calculates values for the gamma distribution, which is a continuous probability distribution commonly used in statistical analysis. The gamma distribution is particularly useful for modeling positive continuous variables and has applications in reliability analysis, queuing theory, and meteorology.

For better accuracy and consistency with other modern statistical functions, it is recommended to use the GAMMA.DIST function . GAMMA.DIST uses the same arguments and provides the same core functionality with improved numerical precision. See the GAMMA.DIST function for more details.

Notes

  • GAMMADIST is a legacy function. For Excel 2010 and later, use the GAMMA.DIST function.
  • If any argument is non-numeric, GAMMADIST returns the #VALUE! error.
  • If x < 0, GAMMADIST returns the #NUM! error.
  • If alpha ≤ 0 or beta ≤ 0, GAMMADIST returns the #NUM! error.
  • In Excel 2007, this is a Statistical function

Purpose

Return value

Syntax

=GAMMAINV(probability,alpha,beta)
  • probability - The probability associated with the gamma distribution (must be between 0 and 1).
  • alpha - The shape parameter of the distribution.
  • beta - The scale parameter of the distribution.

Using the GAMMAINV function

The GAMMAINV function returns the value at which the cumulative gamma distribution reaches a specified probability. For better accuracy and consistency with other modern statistical functions, it is recommended to use the GAMMA.INV function . GAMMA.INV uses the same arguments and provides the same core functionality with improved numerical precision. See the GAMMA.INV function for more details and examples.

Notes

  • GAMMAINV is a legacy function. For Excel 2010 and later, use the GAMMA.INV function.
  • If any argument is non-numeric, GAMMAINV returns the #VALUE! error.
  • If probability < 0 or ≥ 1, GAMMAINV returns the #NUM! error.
  • If alpha ≤ 0 or beta ≤ 0, GAMMAINV returns the #NUM! error.
  • GAMMA.INV provides improved accuracy over the legacy GAMMAINV function.