

   AArriitthhmmeettiicc MMeeaann

        mean(x, trim=0, na.rm=FALSE)

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

          x: a numeric vector containing the values whose mean
             is to be computed.

       trim: the fraction (0 to 0.5) of observations to be
             trimmed from each end of `x' before the mean is
             computed.

      na.rm: a logical value indicating whether `NA' values
             should be stripped before the computation pro-
             ceeds.

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

        If `trim' is zero (the default), the arithmetic mean of
        the values in `x' is computed.  If `trim' is non-zero,
        a symmetrically trimmed mean is computed with a frac-
        tion of `trim' observations deleted from each end
        before the mean is computed.

        Missing values are ignored.

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

        `weighted.mean'

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

        x <- c(0:10, 50)
        xm <- mean(x)
        c(xm, mean(x, trim = .10))

