

   TThhee DDoouubbllee PPooiissssoonn DDiissttrriibbuuttiioonn

        ddoublepois(y, m, s)
        pdoublepois(q, m, s)

   AArrgguummeennttss::

          y: vector of counts

          q: vector of quantiles

          m: vector of means

          s: vector of overdispersion parameters

   VVaalluuee::

        These functions provide information about the double
        Poisson distribution with parameters `m' and `s'.
        `ddoublepois' gives the density and `pdoublepois' gives
        the distribution function.

        The double Poisson distribution with `mu' = m has den-
        sity

          p(y) = c(m,s) s^(y/m) (m/y)^(y log(s)) y^(y-1) / y!

        for y = 0, ..., where c(.) is a normalizing constant.

   SSeeee AAllssoo::

        `dpois' for the Poisson, `dmultpois' for the multi-
        plicative Poisson, and `dnbinom' for the negative bino-
        mial distribution.

   EExxaammpplleess::

        ddoublepois(5,5,0.9)
        pdoublepois(5,5,0.9)

