reg.line {car}R Documentation

Plot Regression Line

Description

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

Usage

reg.line(mod, col=palette()[2], lwd=2, lty=1,...)

Arguments

mod a model, such as produced by lm, that responds to the coefficients 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 color palette (see palette 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.

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.

Value

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

Author(s)

John Fox jfox@mcmaster.ca

See Also

abline, lines

Examples

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

[Package car version 1.1-0 Index]