Amelia Marsh <amelia_marsh08 <at> yahoo.com> writes: > > Dear R forum > > I have following data > > amounts = c(928906.144,156091.0576,433798.3404,993425.7224, > 1323976.364,649106.9339, 369967.2612,2528872.35,1226093.655, > 1145446.149,1809624.453,599329.0394,2200955.213,2583318.064, > 745625.8069,961828.8828,1744841.313,1939390.005,1077873.654, > 729924.2713,803584.2636,287020.8529,530910.9004,818574.0089, > 1908133.51,262336.0893,593808.2542,780258.1354) > # Estimating Gamma distribution parameters > > shape_gamma <- (mean(amounts)/sd(amounts))^2 > > scale_gamma <- (sd(amounts)^2/mean(amounts)) >
The default parameterization of the Gamma distribution in R uses a rate parameter, not a scale parameter. You can override this: Fx <- pgamma(amounts, shape_gamma, scale=scale_gamma) or Fx <- pgamma(amounts, shape_gamma, rate=1/scale_gamma) One place you can find a description of the parameterizations in R is http://journal.r-project.org/archive/2013-1/lebauer-dietze-bolker.pdf ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
