

   MMeeddiiaann PPoolliisshh ooff aa MMaattrriixx

        medpolish(x, eps=0.01, maxiter=10, trace.iter = TRUE)

        plot(medpolish.obj)
        print(medpolish.obj)

   DDeessccrriippttiioonn::

        `medpolish' fits an additive "two-way" (constant + rows
        + columns) model to the values given in `x' using
        Tukey's median polish procedure.

   DDeettaaiillss::

        Sweeping out for row and column effects continues until
        the proportional reduction in the sum of absolute
        residuals is less than `eps' or until there have been
        `maxiter' iterations.  The sum of absolute residuals is
        printed at each iteration of the fitting process, if
        `trace.iter' is `TRUE'.

        `medpolish' returns an object of class `medpolish' (see
        below).  There are printing and plotting methods for
        this class, which are invoked via by the generics
        `print' and `plot'.

   VVaalluuee::

        An object of class `medpolish' with the following named
        components:

    overall: the fitted constant term.

        row: the fitted row effects.

        col: the fitted column effects.

   residuals: the residuals.

       name: the name of the dataset.

   RReeffeerreenncceess::

        Tukey (1977). E.D.A; see ref. in `line'.

   SSeeee AAllssoo::

        `median'; `aov' which for a mean instead of median
        decomposition.

   EExxaammpplleess::

        ## Deaths from sport parachuting;  from ABC of EDA, p.224:
        deaths <-
            rbind(c(14,15,14),
                  c( 7, 4, 7),
                  c( 8, 2,10),
                  c(15, 9,10),
                  c( 0, 2, 0))
        dimnames(deaths) <- list(c("1-24", "25-74", "75-199", "200++", "NA"),
                                 paste(1973:1975))
        deaths
        (med.d <- medpolish(deaths))
        plot(med.d)
        ## Check decomposition:
        all(deaths == med.d$overall + outer(med.d$row,med.d$col, "+") + med.d$resid)

