bxp                   package:base                   R Documentation

Box Plots from Summaries

Description:

     `bxp' draws box plots based on the given summaries in `z'. It is
     usually called from within `boxplot', but can be invoked directly.

Usage:

     bxp(z, notch = FALSE, width = NULL, varwidth = FALSE, outline = TRUE,
         notch.frac = 0.5, boxwex = 0.8, border = par("fg"), col = NULL,
         log = "", pars = NULL, frame.plot = axes, horizontal = FALSE, add = FALSE,
         at = NULL, show.names=NULL, ...)

Arguments:

       z: a list containing data summaries to be used in constructing
          the plots.  These are usually the result of a call to
          `boxplot', but can be generated in any fashion.

   notch: if `notch' is `TRUE', a notch is drawn in each side of the
          boxes.  If the notches of two plots do not overlap then the
          medians are significantly different at the 5 percent level.

   width: a vector giving the relative widths of the boxes making up
          the plot.

varwidth: if `varwidth' is `TRUE', the boxes are drawn with widths
          proportional to the square-roots of the number of
          observations in the groups.

 outline: if `outline' is not true, the boxplot lines are not drawn.

  boxwex: a scale factor to be applied to all boxes.  When there are
          only a few groups, the appearance of the plot can be improved
          by making the boxes narrower.

notch.frac: numeric in (0,1). When `notch=TRUE', the fraction of the
          box width that the notches should use.

  border: character, the color of the box borders.  Is recycled for
          multiple boxes.

     col: character; the color within the box.  Is recycled for
          multiple boxes

     log: character, indicating if any axis should be drawn in
          logarithmic scale, as in `plot.default'.

frame.plot: logical, indicating if a ``frame'' (`box') should be drawn;
          defaults to `TRUE', unless `axes = FALSE' is specified.

horizontal: logical indicating if the  boxplots should be horizontal;
          default `FALSE' means vertical boxes.

     add: logical, if true add boxplot to current plot.

      at: numeric vector giving the locations where the boxplots should
          be drawn, particularly when `add = TRUE'; defaults to `1:n'
          where `n' is the number of boxes.

show.names: Set to `TRUE' or `FALSE' to override the defaults on
          whether an x-axis label is printed for each group.

pars,...: Graphical parameters can be passed as arguments to this
          function, either as a list (`pars') or normally(`...').

Value:

     An invisible vector, actually identical to the `at' argument, with
     the coordinates ("x" if horizontal is false, "y" otherwise) of box
     centers, useful for adding to the plot.

Examples:

     set.seed(753)
     str(bx.p <- boxplot(split(rt(100, 4), gl(5,20))))
     op <- par(mfrow= c(2,2))
     bxp(bx.p, xaxt = "n")
     bxp(bx.p, notch = TRUE, axes = FALSE, pch = 4)
     bxp(bx.p, notch = TRUE, col= "lightblue", frame= FALSE, outl= FALSE,
         main = "bxp(*, frame= FALSE, outl= FALSE)")
     bxp(bx.p, notch = TRUE, col= "lightblue", border="red", ylim = c(-4,4),
         pch = 22, bg = "green", log = "x", main = "... log='x', ylim=*")
     par(op)
     op <- par(mfrow= c(1,2))
     data(PlantGrowth)
     ## single group -- no label
     boxplot(weight~group,data=PlantGrowth,subset=group=="ctrl")
     bx<-boxplot(weight~group,data=PlantGrowth,subset=group=="ctrl",plot=FALSE)
     ## with label
     bxp(bx,show.names=TRUE)
     par(op)

