GAMMAINV(p,alpha,beta)
GAMMAINV function returns the inverse of the cumulative gamma distribution.
If @p < 0 or @p > 1 GAMMAINV returns #NUM! error. If @alpha <= 0 or @beta <= 0 GAMMAINV returns #NUM! error. This function is Excel compatible.
GAMMAINV(0.34,2,4) equals 4.829093908.
GAMMADIST