regLine {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

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

### 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.

### 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)
    regLine(lm(repwt~weight, subset=sex=="M", data=Davis))
    regLine(lm(repwt~weight, subset=sex=="F", data=Davis), lty=2)

[Package car version 3.0-0 Index]