Draw multibox plot(s) for given (grouped) values, possibly asymmetric. 'plbox' draws a single multibox plot (low level graphical function). 'plboxes' is a high level graphics function that draws multiboxes for grouped data. A secondary, binary grouping factor can be given to produce asymmetric multiboxes.
plmboxes(x, ...)
# S3 method for formula
plmboxes(x, y=NULL, data, ...)# S3 method for default
plmboxes(x=NULL, y=NULL, data=NULL, width=1, at=NULL,
horizontal=FALSE,
probs=NULL, outliers=TRUE, na=FALSE, backback=NULL, refline=NULL,
add=FALSE, xlim=NULL, ylim=NULL, axes=TRUE, xlab=NULL, ylab=NULL,
labelsperp=FALSE, xmar=NULL, mar=NULL,
widthfac=NULL, minheight=NULL, colors=NULL, lwd=NULL,
.subdefault=NULL, plargs = NULL, ploptions = NULL, marpar = NULL, ...)
plmbox(x, at=0, probs=NULL, outliers=TRUE, na.pos=NULL, horizontal=FALSE,
width=1, wfac=NULL, minheight=NULL, adj=0.5, extquant=FALSE,
widthfac=c(max=2, med=1.3, medmin=0.3, outl=NA),
colors=c(box="lightblue2",med="blue",na="gray90"),
lwd=c(med=3, range=2), warn=options("warn"))
plmboxes invisibly returns the 'at' values that are finally
used.\
plmbox returns a scalar by which the width of the boxes are
multiplied for plotting,
and, as attributes, the quantiles and widths used to draw the boxes
For 'plmboxes.formula': a formula, such as 'y ~ grp' or 'y~grp+grp2', where 'y' is a numeric vector of data values to be split into groups according to the grouping variable 'grp' (usually a factor) and, if given, according to the binary variable 'grp2'. 'y~1+grp2' produces a single asymmetric mbox.
For 'plmboxes.default': factor to be used as the grouping variable or matrix or data.frame with 2 columns (for asymmetric mbox plot), where the second column is binary.
a numeric vector of data values
a data.frame from which the variables in 'formula' should be taken.
a vector giving the widths of the multibox plot for each group 'grp1'.
horizontal position of the multiboxes. Must have length equal to the number of (present) levels of the factor 'grp'. if an element of 'at' is 'NA', the group will be skipped. Defaults to 1, 2, ...
logical. If TRUE, boxes will be drawn horizontally. Note that 'y' is then the horizontal coordinate, i.e., still the quantitative variable defining the boxes, and 'x' is still the grouping.
probability values for selecting the quantiles. If all 'probs' are <=0.5, they will be mirrored at 0.5 for 'plmboxes'. The default is c(0.05,0.25,0.5) if the average number of data per group (for 'plmboxes', or the number of data, for 'plmbox') is less than 20, c(0.025,0.05,0.125,0.25,0.375,0.5), otherwise.
logical: should outliers be marked?
if 'na' is not NULL, NA values will be represented by a box. If 'na' is TRUE, the position of the box will be generated to be below the minimum of the data. If 'na' (for 'plmboxes') or 'na.pos' (for 'plmbox') is a scalar or a vector of length 2, the position of the box is at that value (with a generated width) or between the 2 values, respectively.
logical: Should two back-to-back multiboxes be displayed if the (single) x factor is binary?
vertical positions of any horizontal reference lines
logical. If TRUE, the mboxes will be added to an existing plot without calling 'plot'.
plotting limits for the horizontal axis.
plotting limits for the vertical axis.
logical. If FALSE, no axes are drawn.
label for the x axis. Defaults to the "x factor" -- the first name on the right hand side of 'formula'
label for the x axis. Defaults to the left hand side of 'formula'.
logical: Should the labels for the levels of the "x factor" be shown in perpendicular to the axis? If it is numeric, it determines the maximum label length, with a maximum of 20.
plot margin for the "x factor" axis.
Default tries to be suitable, i.e. expand the margin if
labelsperp is TRUE according to the length of the
levels' labels. If xmar has two more elements,
they determine the margin lines where the variable label and the levels'
labels are shown.
margin widths
named vector used to modify the following settings:
max=2: determes the maximal width of the boxes.
Boxes that should be wider are censored and marked as such.
med=1.3, medmin=0.3: determine the width of the mark for the data median.
The width is 'med' times the maximal width of the boxes,
but at least 'medmin'.
outl=NA: length of the marks for outliers.
sep=0.003: width of the gap between the "half" mbox plots in case of
asymmetric mboxes (only needed for 'plmboxes').
For 'plmboxes', the argument needs to contain only the elements that
should be different from the default values.
named vector or list selecting the colors to be used, with named elements:
box="lightblue2": color with which the central box(es) (those corresponding to probabilieties between 0.25 and 0.75) will be filled.
med="blue": color of the mark for the median.
na="grey90": color with which the box for NA values will be filled.
For 'plmboxes', the argument needs to contain only the elements that should be different from the default values.
named vector or list selecting the line width to be used, with named elements:
med=3: line width for the mark showing the median
range=2: line width for the line along the range of the data
For 'plmboxes', the argument needs to contain only the elements that should be different from the default values.
result of calling pl.control.
If NULL, pl.control will be called to generate it.
If not null, arguments given in ... will be ignored.
list of pl options.
margin parameters, if already available.
By default, they will be retieved from ploptions.
additional arguments passed to 'plot'
text for the subtitle in case that it is not specified
Specific arguments for 'plmbox':
factor by which the widths of the boxes must be multiplied. If given, it overrides 'width'
minimal class width ("height") for the boxes (in case two quantiled are [almost] identical). The default is 0.02 times the (median of the within group) IQR.
adjustment of the boxes. 'adj=0' leads to boxes aligned on the left, 'adj=1', on the right, 'adj=0.5', centered. Other values of 'adj' make little sense.
logical, passed to quinterpol:
Should the quantiles be extrapolated beyond the range of the data?
This may make sense if the sample is small or the data is rounded
or grouped or a score.
level of warning for the case when there is no non-missing data
Werner A. Stahel
A multibox plot is a generalization (and modification) of the ordinary box plot that draws more details of the distribution in the form of a histogram with variable class widths. The classes are selected such that preselected quantiles form the class breaks. By default, these quantiled include the median and the quartiles, thereby recovering the box of the traditional box plot.
plmboxes(Sepal.Length~Species, data=iris)
plmboxes(Sepal.Length~Species, data=iris,
widthfac=c(med=2), colors=c(med="red"), horizontal=TRUE)
plmboxes(Sepal.Length~factor(Species)+I(Sepal.Width<=3), data=iris[1:100,],
labelsperp=TRUE, horizontal=TRUE)
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