The R Project SVN R

\name{Exponential}
\title{The Exponential Distribution}
\usage{
dexp(x, rate=1)
pexp(q, rate=1)
qexp(p, rate=1)
rexp(n, rate=1)
}
\alias{dexp}
\alias{pexp}
\alias{qexp}
\alias{rexp}
\arguments{
\item{x,q}{vector of quantiles.}
\item{p}{vector of probabilities.}
\item{n}{number of observations to generate.}
\item{rate}{vector of rates.}
}
\value{
These functions provide information about the exponential
distribution with rate \code{rate} (i.e. mean \code{1/rate}).
\code{dexp} gives the density,
\code{pexp} gives the distribution function
\code{qexp} gives the quantile function
and
\code{rexp} generates random deviates.

The exponential distribution with rate \eqn{\lambda}
has density
\deqn{f(x) =
\lambda {e}^{- \lambda x}}{f(x) = lambda e^-( lambda x)}
for \eqn{x \ge 0}.
}
\seealso{
\code{\link{exp}}, \code{\link{dchisq}} for the chisquare and
\code{\link{dweibull}} for the Weibull distribution which both generalize the
exponential.
}
\examples{
dexp(1) - exp(-1) #-> 0
r <- rexp(100)
all(abs(1 - dexp(1, r) / (r*exp(-r))) < 1e-14)
}
\keyword{distribution}