WorksheetFunction.GammaInv Method
| Excel Developer Reference |
Returns the inverse of the gamma cumulative distribution. If p = GAMMADIST(x,...), then GAMMAINV(p,...) = x.
Syntax
expression.GammaInv(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, GAMMAINV returns the standard gamma distribution. |
Return Value
Double
Remarks
You can use this function to study a variable whose distribution may be skewed.
- If any argument is text, GAMMAINV returns the #VALUE! error value.
- If probability < 0 or probability > 1, GAMMAINV returns the #NUM! error value.
- If alpha ≤ 0 or if beta ≤ 0, GAMMAINV returns the #NUM! error value.
Given a value for probability, GAMMAINV seeks that value x such that GAMMADIST(x, alpha, beta, TRUE) = probability. Thus, precision of GAMMAINV depends on precision of GAMMADIST. GAMMAINV uses an iterative search technique. If the search has not converged after 100 iterations, the function returns the #N/A error value.
See Also