

   TThhee CChhii--SSqquuaarree DDiissttrriibbuuttiioonn

        dchisq(x, df)
        pchisq(q, df)
        qchisq(p, df)
        rchisq(n, df)

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

        These functions provide information about the chi-
        square distribution with `df' degrees of freedom.
        `dchisq' gives the density, `pchisq' gives the distri-
        bution function `qchisq' gives the quantile function
        and `rchisq' generates random deviates.

        The chi-square distribution with `df' = n degrees of
        freedom has density

          f(x) = 1 / (2^(n/2) Gamma(n/2))  x^(n/2-1) e^(-x/2)

        for x > 0.

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

        `dnchisq', `dgamma', `dexp'.

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

        dchisq(1, df=1:3)
        x <- 1:10
        ## Chisquare( df = 2) is a special exponential distribution
        dchisq(x, df=2) == dexp(x, 1/2)
        pchisq(x, df=2) == pexp(x, 1/2)#- only approximately

