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Box Plots

Syntax

boxplot(..., range=1.5, width, varwidth=false,
    notch=false, names, plot=true, col, fill=null)

Arguments

... either vectors or a list containing the values to appear in the boxplots (NAs are allowed).
range this determines how far the plot whiskers extend out from the box. If range is positive, the whiskers extend to the most extreme data point which is no more than range times the interquartile range from the box. A value of zero causes the whiskers to extend to the data extremes.
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.
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.
name group labels which while be printed under each boxplot.
plot if plot is true (the default) then a boxplot is produced. If not, the summaries which the boxplots are based on are returned.
col an optional vector of colors for the outlines of the boxplots. The values in col are recycled if the length of col is less than the number of plots.
fill if fill is non-null it is assumed to contain colors to be used to fill the bodies of the box plots.

Description

boxplot produces box-and-whisker plots of the given values. The data which are used to construct plots may be passed as a sequence of vector arguments, or as a single list of vectors. The command split can be used to create the right kind of list.

Values

A list with one component corresponding to each plot. The components are themselves lists with named components as follows:
stats a vector containing the extreme of the lower whisker, the lower hinge, the median, the upper hinge and the extreme of the upper whisker. n the number of observations in the sample. conf the lower and upper extremes of the notch. out the values of any data points which lie beyond the extremes of the whiskers.

Examples

boxplot(precipitation) boxplot(split(warpbreaks,col(warpbreaks,factor=true)))