car (version 3.1-2)

regLine: Plot Regression Line

Description

Plots a regression line on a scatterplot; the line is plotted between the minimum and maximum x-values.

Usage

regLine(mod, col=carPalette()[2], lwd=2, lty=1,...)

Value

NULL. This function is used for its side effect: adding a line to the plot.

Arguments

mod

a model, such as produced by lm, that responds to the coef function by returning a 2-element vector, whose elements are interpreted respectively as the intercept and slope of a regresison line.

col

color for points and lines; the default is the second entry in the current car palette (see carPalette and par).

lwd

line width; default is 2 (see par).

lty

line type; default is 1, a solid line (see par).

...

optional arguments to be passed to the lines plotting function.

Author

John Fox

Details

In contrast to abline, this function plots only over the range of the observed x-values. The x-values are extracted from mod as the second column of the model matrix.

See Also

abline, lines

Examples

plot(repwt ~ weight, pch=c(1,2)[sex], data=Davis)
regLine(lm(repwt~weight, subset=sex=="M", data=Davis))
regLine(lm(repwt~weight, subset=sex=="F", data=Davis), lty=2)