car: Boxplot – R documentation

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Boxplot

Boxplots With Point Identification

Description

Boxplot is a wrapper for the standard R boxplot function, providing point identification, axis labels, and a formula interface for boxplots without a grouping variable.

Usage

Boxplot(y, ...)

## Default S3 method:
Boxplot(y, g, id=TRUE, xlab, ylab, ...)

## S3 method for class 'formula'
Boxplot(formula, data=NULL, subset, na.action=NULL, 
    id=TRUE, xlab, ylab, ...)

## S3 method for class 'list'
Boxplot(y, xlab="", ylab="", ...)

## S3 method for class 'data.frame'
Boxplot(y, id=TRUE, ...)

## S3 method for class 'matrix'
Boxplot(y, ...)

Arguments

`y`	a numeric variable for which the boxplot is to be constructed; a list of numeric variables, each element of which will be treated as a group; a numeric data frame or a numeric matrix, each of whose columns will be treated as a group.
`g`	a grouping variable, usually a factor, for constructing parallel boxplots.
`id`	a list of named elements giving one or more specifications for labels of individual points ("outliers"): `n`, the maximum number of points to label (default 10); `location`, `"lr"` (left or right) of points or `"avoid"` to try to avoid overplotting; `method`, one of `"y"` (automatic, the default), `"identify"` (interactive), or `"none"`; `col` for labels (default is the first color in `carPalette()` ); and `cex` size of labels (default is `1`). Can be `FALSE` to suppress point identification or `TRUE` (the default) to use all defaults. This is similar to how `showLabels` handles point labels for other functions in the car package, except that the usual default is `id=FALSE`.
`xlab, ylab`	text labels for the horizontal and vertical axes; if missing, `Boxplot` will use the variable names, or, in the case of a list, data frame, or matrix, empty labels.
`formula`	a ‘model’ formula, of the form `~ y` to produce a boxplot for the variable `y`, or of the form `y ~ g`, `y ~ g1g2...`, or `y ~ g1 + g2 + ...` to produce parallel boxplots for `y` within levels of the grouping variable(s) `g`, etc., usually factors.
`data, subset, na.action`	as for statistical modeling functions (see, e.g., `lm`).
`...`	further arguments, such as `at`, to be passed to `boxplot`.

Author(s)

John Fox jfox@mcmaster.ca, with a contribution from Steve Ellison to handle at argument (see boxplot).

References

Fox, J. and Weisberg, S. (2019) An R Companion to Applied Regression, Third Edition, Sage.

Examples

Boxplot(~income, data=Prestige, id=list(n=Inf)) # identify all outliers
Boxplot(income ~ type, data=Prestige)
Boxplot(income ~ type, data=Prestige, at=c(1, 3, 2))
Boxplot(k5 + k618 ~ lfp*wc, data=Mroz)
with(Prestige, Boxplot(income, id=list(labels=rownames(Prestige))))
with(Prestige, Boxplot(income, type, id=list(labels=rownames(Prestige))))
Boxplot(scale(Prestige[, 1:4]))

car

Companion to Applied Regression

v3.0-10

GPL (>= 2)

Authors

John Fox [aut, cre], Sanford Weisberg [aut], Brad Price [aut], Daniel Adler [ctb], Douglas Bates [ctb], Gabriel Baud-Bovy [ctb], Ben Bolker [ctb], Steve Ellison [ctb], David Firth [ctb], Michael Friendly [ctb], Gregor Gorjanc [ctb], Spencer Graves [ctb], Richard Heiberger [ctb], Pavel Krivitsky [ctb], Rafael Laboissiere [ctb], Martin Maechler [ctb], Georges Monette [ctb], Duncan Murdoch [ctb], Henric Nilsson [ctb], Derek Ogle [ctb], Brian Ripley [ctb], William Venables [ctb], Steve Walker [ctb], David Winsemius [ctb], Achim Zeileis [ctb], R-Core [ctb]

Initial release

2020-09-23