The R Project SVN R

\name{GammaDist}
\title{The Gamma Distribution}
\usage{
dgamma(x, shape, scale=1)
pgamma(q, shape, scale=1)
qgamma(p, shape, scale=1)
rgamma(n, shape, scale=1)
}
\alias{dgamma}
\alias{pgamma}
\alias{qgamma}
\alias{rgamma}
\arguments{
\item{x,q}{vector of quantiles.}
\item{p}{vector of probabilites.}
\item{n}{number of observations.}
\item{shape, scale}{shape and scale parameters.}
}
\value{
These functions provide information about the gamma
distribution with parameters \code{shape} and \code{scale}.
\code{dgamma} gives the density,
\code{pgamma} gives the distribution function
\code{qgamma} gives the quantile function
and
\code{rgamma} generates random deviates.

The gamma distribution with parameters \code{shape} \eqn{= a} and
\code{scale} \eqn{= b} has density
\deqn{f(x) =
\frac{1}{{b}^{a} \Gamma (a)} {x}^{a-1} {e}^{-x/b}}{f(x) = 1/(b^a Gamma(a)) x^(a-1) e^-(x/b)}
for \eqn{x > 0},
\eqn{a > 0}
and
\eqn{b > 0}.
}
\seealso{
\code{\link{gamma}}, \code{\link{dbeta}}.
}
\examples{
-log(dgamma(1:4, shape=1))
p <- (1:9)/10
pgamma(qgamma(p,shape=2), shape=2)
1 - 1/exp(qgamma(p, shape=1))
}
\keyword{distribution}