

   CCoorrrreellaattiioonn aanndd CCoovvaarriiaannccee MMaattrriicceess

        cor(x, y=x, use="all.obs")
        cov(x, y=x, use="all.obs")

   AArrgguummeennttss::

          x: a matrix or data frame.

          y: a matrix or data frame.

        use: a character string giving the method for handling
             missing observations. This must be one of the
             stringss `"all.obs"', `"complete.obs"' or `"pair-
             wise.complete.obs"' (abbreviations are accept-
             able).

   VVaalluuee::

        The correlation matrix or covariance matrix of the
        columns of `x' and the columns of `y'.

        If `use' has the value `"all.obs"', then the presence
        of missing observations will cause the computation to
        fail.  If `use' has the value `"complete.obs"' then
        missing values are handled by casewise deletion.
        Finally, if `use' has the value `"pairwise.com-
        plete.obs"' then the correlation between each pair of
        variables is computed using all complete pairs of
        observations on those variables.  This can result in
        correlation matrices which are not positive semidefi-
        nite.

