heplots (version 1.3-1)

coefplot: Coefficient plots for Multivariate Linear Models

Description

Displays confidence ellipses for all parameters in an multivariate linear model, for a given pair of variables. As such, it is a generalization of confidenceEllipse.

Usage

coefplot(object, ...)
"coefplot"(object, variables = 1:2, parm = NULL, 
	df = NULL, level = 0.95, intercept = FALSE, 
	Scheffe = FALSE, bars = TRUE, 
	fill = FALSE, fill.alpha = 0.2, 
	labels = !add, label.pos = NULL, 
	xlab, ylab, 
	xlim = NULL, ylim = NULL, 
	axes = TRUE, main = "", add = FALSE, 
	lwd = 1, lty = 1, pch = 19, col = palette(), 
	cex = 2, cex.label = 1.5, 
	lty.zero = 3, col.zero = 1, pch.zero = '+',
	verbose = FALSE, ...)

Arguments

object

A multivariate linear model, such as fit by lm()

...

Other parameters passed to methods

variables

Response variables to plot, given as their indices or names

parm

Parameters to plot

df

Degrees of freedom for hypothesis tests

level

Confidence level

intercept

logical. Include the intercept?

Scheffe

If TRUE, confidence intervals for all parameters have Scheffe coverage, otherwise, individual coverage.

bars

Draw univariate confidence intervals for each of the variables?

fill

a logical value or vector. TRUE means the confidence ellipses will be filled.

fill.alpha

labels

Labels for the confidence ellipses

label.pos

Positions of the labels for each ellipse. See label.ellipse

xlab, ylab

x, y axis labels

xlim, ylim

Axis limits

axes

Draw axes?

main

Plot title

add

logical. Add to an existing plot?

lwd

Line widths

lty

Line types

pch

Point symbols for the parameter estimates

col

Colors for the confidence ellipses, points, lines

cex

Character size for points showing parameter estimates

cex.label

Character size for ellipse labels

lty.zero, col.zero, pch.zero

Line type, color and point symbol for horizontal and vertical lines at 0, 0.

verbose

logical. Print parameter estimates and variance-covariance for each parameter?

Value

Returns invisibly a list of the coordinates of the ellipses drawn

See Also

confidenceEllipse, ~~~

Examples

mod <- lm(cbind(SAT,PPVT,Raven)~n+s+ns, data=Rohwer)

coefplot(mod, lwd=2, main="Bivariate coefficient plot for SAT and PPVT", fill=TRUE)
coefplot(mod, add=TRUE, Scheffe=TRUE, fill=TRUE)

coefplot(mod, var=c(1,3))

mod1 <- lm(cbind(SAT,PPVT,Raven)~n+s+ns+na+ss, data=Rohwer)
coefplot(mod1, lwd=2, fill=2 !=(1:5),
	main="Bivariate 68% coefficient plot for SAT and PPVT", level=0.68)