WorksheetFunction.Gamma_Inv Method (Excel)
Returns the inverse of the gamma cumulative distribution. If p = GAMMA_DIST(x,...), then GAMMA_INV(p,...) = x.
Version Information
Version Added: Excel 2010
Syntax
expression .Gamma_Inv(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, GAMMA_INV 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, GAMMA_INV returns the #VALUE! error value.
If probability < 0 or probability > 1, GAMMA_INV returns the #NUM! error value.
If alpha ≤ 0 or if beta ≤ 0, GAMMA_INV returns the #NUM! error value.
Given a value for probability, GAMMA_INV seeks that value x such that GAMMA_DIST(x, alpha, beta, TRUE) = probability. Thus, precision of GAMMA_INV depends on precision of GAMMA_DIST. GAMMA_INV uses an iterative search technique. If the search has not converged after 100 iterations, the function returns the #N/A error value.