Abstract
As a unified functional model of frequency distribution of the variouE amounts of precipitation, hyper Gamma distribution function, is proposed to contain the past several functional distributions as the special cases by author.
Moment estim a tes and maximum likelihood estimates of parameters, α, β and υ are studied and variance matrix of maximum likelihood estimates is asymptotically gained, and test result of fitness to actual frequency distribution shows the satisfactory fittness exceeding the fast functional types.
Several necessary diagrams to gain moment estimates are supplemented for this paper.
