

   TThhee NNoonn--CCeennttrraall CChhii--SSqquuaarree DDiissttrriibbuuttiioonn

        dnchisq(x, df, lambda)
        pnchisq(q, df, lambda)
        qnchisq(p, df, lambda)
        rnchisq(n, df, lambda)

   DDeessccrriippttiioonn::

        These functions provide information about the non-cen-
        tral chi-square distribution with `df' degrees of free-
        dom and non-centrality parameter `lambda'.  `dnchisq'
        gives the density, `pnchisq' gives the distribution
        function, `qnchisq' gives the quantile function and
        `rnchisq' generates random deviates.

        The non-central chi-square distribution with df degrees
        of freedom and non-centrality parameter lambda has den-
        sity

        f(x) = exp(-lambda/2) SUM_{r=0}^infty (lambda^r / 2^r r!)
        pchisq(x, df + 2r)

        for x >= 0.

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

        `dchisq', `dgamma'.

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

        pnchisq(1, df = 3, lambda = 0) == pchisq(1, df = 3)
        pnchisq(1, df = 3, lambda = 0:4)

