.BG
.FN boxplot
.TL
Box Plots
.CS
boxplot(..., range, width, varwidth=FALSE,
        notch=FALSE, names, plot=TRUE, old=FALSE)
.AG ...
vectors or a list containing a number of
numeric components (e.g., the output of `split').
Note that all other arguments must be specified by exact name.
.NA
.AG range=
controls the strategy for the whiskers and the detached
points beyond the whiskers. By default, whiskers are drawn
to the nearest value not beyond a standard range from the quartiles; points
beyond are drawn individually.  Giving `range=0' forces
whiskers to the full data range. Any positive value of
`range' multiplies the standard range by this amount.
The standard range is 1.5*(inter-quartile range).
.AG width=
vector of relative box widths.  See also argument
`varwidth'.
.AG varwidth=
if `TRUE', box widths will be proportional to
the square-root of the number of observations for the box.
.AG notch=
if `TRUE', notched boxes are drawn, where
non-overlapping of notches of boxes indicates a difference at a
rough 5% significance level.
.AG names=
optional character vector of names for the groups.  If
omitted, names used in labelling the plot will be taken from
the names of the arguments and from the names attribute of lists.
.AG plot=
if `TRUE', the box plot will be produced;
otherwise, the calculated summaries of the arguments are
returned.
.AG old=
if `TRUE', the plot will be produced in the style described in
the Tukey (1977) reference;
otherwise, the plot will follow the more modern style introduced
in Tukey (1989), where
the advantages of the new style are described.
.GR
.RT
if `plot' is `FALSE', a list with the
components listed below.  Otherwise function `bxp' is
invoked with these components, plus optional
`width', `varwidth' and `notch', to produce the plot.
Note that `bxp' returns a vector of box centers.
.PP
.RC stats
matrix (5 by number of boxes) giving the upper extreme,
upper quartile, median, lower quartile, and lower extreme
for each box.
.RC n
the number of observations in each group.
.RC conf
matrix (2 by number of boxes) giving confidence limits for
median.
.RC out
optional vector of outlying points.
.RC group
vector giving the box to which each point in `out' belongs.
.RC names
names for each box (see argument `names' above).
.SA
`bxp'.
.SH REFERENCE
Tukey, John W., 
.ul
Exploratory Data Analysis,
Addison-Wesley, Reading, Mass.,
1977.
.sp
Tukey, John W., "Data Based Graphics: Visual Display in the Decades to Come",
.ul
Proc. Am. Stat. Assn, Sesquicentennial Invited Paper Sessions,
pp. 366-381, 1989.
.EX
boxplot(group1,group2,group3)

boxplot(split(salary,age),varwidth=TRUE,notch=TRUE)

# the example plot is produced by:
boxplot(
      split(lottery.payoff,lottery.number%/%100),
      main=lottery.label,
      sub="Leading Digit of Winning Numbers",
      ylab="Payoff")
.PI
.KW hplot
.KW dplot
.WR
