

   CCoorrrreellaattiioonn CCooeeffffiicciieenntt

        corr(d, w=rep(1,nrow(d))/nrow(d))

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

          d: A matrix with two columns corresponding to the two
             variables whose correlation we wish to calculate.

          w: A vector of weights to be applied to each pair of
             observations.  The default is equal weights for
             each pair.  Normalization takes place within the
             function so `sum(w)' need not equal 1.

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

        Calculates the weighted correlation given a data set
        and a set of weights.

   DDeettaaiillss::

        This function finds the correlation coefficient in
        weighted form.  This is often useful in bootstrap meth-
        ods since it allows for numerical differentiation to
        get the empirical influence values.  It is also neces-
        sary to have the statistic in this form to find ABC
        intervals.

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

        The correlation coefficient between `d[,1]' and
        `d[,2]'.

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

        `cor'

