A note on a gamma distribution computer program

The gamma (Pearson Type III) distribution function may be used as a model for many types of data. The electronic computer program for this function in the Formula Translator (FORTRAN) IV (1) provides the analytic solution to a set of data, (2) gives the probabilities of exceeding or not exceeding arbitrary amounts, (3) indicates the amounts exceeded or not exceeded for arbitrary probabilities, (4) provides options to use the biased or unbiased estimates of the maximum likelihood or Thom estimators or to use moment estimators, (5) provides options to provide confidence bands and intervals in tabular and/or graphical forms, and (6) provides for computer output to microfilm or drum and/or flatbed plotters. The programs in their previous forms (EDS 11 and 24) permit a maximum of 52 entries, which will suffice for those dealing with weekly data through the year. In addition, such as in weekly precipitation studies, the user has the option to compute the two- and three-week duration period distributions in one pass of the data. Those computations are done without program change but by appropriate changes in the control cards. Mixed distributions of the zeros and actual amounts are considered. That feature is not limitedto the study of precipitation data nor to the time intervals used. This program is restricted to one string of data of any number but witha maximum of up to 500 data points. An option permits the computation of the required probabilities and inverses when only the scale and shape parameters are given.