Box-percentile plots

Producess side-by-side box-percentile plots from several vectors or a list of vectors.

Usage

bpplot(..., name=TRUE, main="Box-Percentile Plot", 
       xlab="", ylab="", srtx=0, plotopts=NULL)

Arguments

...: vectors or lists containing numeric components (e.g., the output of split).
name: character vector of names for the groups. Default is TRUE to put names on the x-axis. Such names are taken from the data vectors or the names attribute of the first argument if it is a list. Set name to FALSE to suppress names. If a character vector is supplied the names in the vector are used to label the groups.
main: main title for the plot.
xlab: x axis label.
ylab: y axis label.
srtx: rotation angle for x-axis labels. Default is zero.
plotopts: a list of other parameters to send to plot

Value

There are no returned values

Side Effects

A plot is created on the current graphics device.

BACKGROUND

Box-percentile plots are similiar to boxplots, except box-percentile plots supply more information about the univariate distributions. At any height the width of the irregular "box" is proportional to the percentile of that height, up to the 50th percentile, and above the 50th percentile the width is proportional to 100 minus the percentile. Thus, the width at any given height is proportional to the percent of observations that are more extreme in that direction. As in boxplots, the median, 25th and 75th percentiles are marked with line segments across the box.

Author

Jeffrey Banfield
umsfjban@bill.oscs.montana.edu
Modified by F. Harrell 30Jun97

References

Esty WW, Banfield J: The box-percentile plot. J Statistical Software 8 No. 17, 2003.

Examples

set.seed(1)
x1 <- rnorm(500)
x2 <- runif(500, -2, 2)
x3 <- abs(rnorm(500))-2
bpplot(x1, x2, x3)

g <- sample(1:2, 500, replace=TRUE)
bpplot(split(x2, g), name=c('Group 1','Group 2'))

rm(x1,x2,x3,g)