Plot Conditional Densities

Plot conditional densities by group. For describing how the conditional distribution of a categorical variable y changes over a numerical variable x we have the function cdplot. But if we want to compare multiple densities much work is required. PlotConDens allows to easily enter a grouping variable.

PlotConDens(formula, data, col = NULL, lwd = 2, lty = 1, xlim = NULL, rev = TRUE, 
            args.dens = NULL, ...)

Arguments

formula

a "formula" of type y ~ x | g with a single dependent factor, a single numerical explanatory variable and a grouping factor g.

data

a data frame containing values for any variables in the formula. By default the environment where PlotConDens was called from is used.

col

a vector of colors to be used to plot the lines. If too short, the values are recycled.

lwd

a vector of linewidths to be used to plot the lines. If too short, the values are recycled.

lty

a vector of linetypes to be used to plot the lines. If too short, the values are recycled.

xlim

the range for the x axis.

rev

logical, should the values of the response variable be reversed? Default is TRUE.

args.dens

additional arguments for the densitiy curves.

...

the dots are passed on to plot().

Details

Especially when we're modelling binary response variables we might want to know, how the binary variable behaves along some numeric predictors.

Value

the functions for the curves

Author

Andri Signorell <andri@signorell.net>

See also

cdplot, spineplot, density, PlotMultiDens

Examples

data(Pima.tr2, package="MASS")
PlotConDens (type ~ age | I((npreg > 0)*1L), 
             data=Pima.tr2, col=c(DescTools::hblue, DescTools::hred), rev=FALSE, 
             panel.first=quote(grid()))