This function returns the quantile of the gamma distribution. If
p = GAMMA.DIST(x,…), then GAMMA.INV(p,…) = x.
Use this function to examine a variable whose distribution may be skewed.
Syntax:
GAMMA.INV(probability; alpha; beta)
Arguments:
- probability(required) – A probability associated with the gamma distribution.
- alpha(required) – A parameter of the distribution.
- beta(required) – A parameter of the distribution. If beta = 1, INV() returns the standard gamma distribution.
Background:
GAMMA.INV() is the inverse function of GAMMA.DIST() and can be used to model a gamma distribution. The alpha and beta arguments correspond to the values for the GAMMA.DIST() function. The probability can be any value from 0 through 100 percent. GAMMA.INV() calculates the position of x on the horizontal axis that matches the cumulative area ratio of the gamma distribution.
Example:
Use the values in Figure below to calculate GAMMA.INV(). The figure also shows the calculation of GAMMA.INV().
The GAMMA.INV() function returns the quantile 10 for the gamma distribution based on the parameters shown.