

   TThhee GGaammmmaa DDiissttrriibbuuttiioonn

        dgamma(x, shape, scale=1)
        pgamma(q, shape, scale=1)
        qgamma(p, shape, scale=1)
        rgamma(n, shape, scale=1)

   AArrgguummeennttss::

        x,q: vector of quantiles.

          p: vector of probabilites.

          n: number of observations.

   shape, scale: shape and scale parameters.

   VVaalluuee::

        These functions provide information about the gamma
        distribution with parameters `shape' and `scale'.
        `dgamma' gives the density, `pgamma' gives the distri-
        bution function `qgamma' gives the quantile function
        and `rgamma' generates random deviates.

        If `scale' is omitted, it assumes the default value of
        `1'.

        The gamma distribution with parameters `shape' = a and
        `scale' = b has density

               f(x) = 1/(b^a Gamma(a)) x^(a-1) e^-(x/b)

        for x > 0, a > 0 and b > 0.

   SSeeee AAllssoo::

        `gamma' for the gamma function, `dbeta' for the beta
        distribution and `dchisq' for the chi-square distribu-
        tion which is a special case of the gamma distribution.

   EExxaammpplleess::

        -log(dgamma(1:4, shape=1))
        p <- (1:9)/10
        pgamma(qgamma(p,shape=2), shape=2)
        1 - 1/exp(qgamma(p, shape=1))

