histbackback function

Back to Back Histograms

Takes two vectors or a list with x and y components, and produces back to back histograms of the two datasets.

histbackback(x, y, brks=NULL, xlab=NULL, axes=TRUE, probability=FALSE,
             xlim=NULL, ylab='', ...)

Arguments

• x,y: either two vectors or a list given as x with two components. If the components have names, they will be used to label the axis (modification FEH).
• brks: vector of the desired breakpoints for the histograms.
• xlab: a vector of two character strings naming the two datasets.
• axes: logical flag stating whether or not to label the axes.
• probability: logical flag: if TRUE, then the x-axis corresponds to the units for a density. If FALSE, then the units are counts.
• xlim: x-axis limits. First value must be negative, as the left histogram is placed at negative x-values. Second value must be positive, for the right histogram. To make the limits symmetric, use e.g. ylim=c(-20,20).
• ylab: label for y-axis. Default is no label.
• ...: additional graphics parameters may be given.

Returns

a list is returned invisibly with the following components:

• left: the counts for the dataset plotted on the left.

• right: the counts for the dataset plotted on the right.

• breaks: the breakpoints used.

Side Effects

a plot is produced on the current graphics device.

Author(s)

Pat Burns

Salomon Smith Barney

London

pburns@dorado.sbi.com

See Also

hist, histogram

Examples

options(digits=3)
set.seed(1)
histbackback(rnorm(20), rnorm(30))

fool <- list(x=rnorm(40), y=rnorm(40))
histbackback(fool)
age <- rnorm(1000,50,10)
sex <- sample(c('female','male'),1000,TRUE)
histbackback(split(age, sex))
agef <- age[sex=='female']; agem <- age[sex=='male']
histbackback(list(Female=agef,Male=agem), probability=TRUE, xlim=c(-.06,.06))