plotMeans: Plot Means for One or Two-Way Layout

Description

Plots cell means for a numeric variable in each category of a factor or in each combination of categories of two factors, optionally along with error bars based on cell standard errors or standard deviations.

Usage

plotMeans(response, factor1, factor2, 
    error.bars = c("se", "sd", "conf.int", "none"),
    level=0.95, xlab=deparse(substitute(factor1)), 
    ylab=paste("mean of", deparse(substitute(response))),
    legend.lab=deparse(substitute(factor2)), 
    legend.pos=c("farright", "bottomright", "bottom", "bottomleft", 
                 "left", "topleft", "top", "topright", "right", "center"),
    main="Plot of Means",
    pch=1:n.levs.2, lty=1:n.levs.2, col=palette(), connect=TRUE, ...)

Value

The function invisibly returns NULL.

Arguments

response: Numeric variable for which means are to be computed.
factor1: Factor defining horizontal axis of the plot.
factor2: If present, factor defining profiles of means
error.bars: If "se", the default, error bars around means give plus or minus one standard error of the mean; if "sd", error bars give plus or minus one standard deviation; if "conf.int", error bars give a confidence interval around each mean; if "none", error bars are suppressed.
level: level of confidence for confidence intervals; default is .95
xlab: Label for horizontal axis.
ylab: Label for vertical axis.
legend.lab: Label for legend.
legend.pos: Position of legend; if "farright" (the default), extra space is left at the right of the plot.
main: Label for the graph.
pch: Plotting characters for profiles of means.
lty: Line types for profiles of means.
col: Colours for profiles of means
connect: connect profiles of means, default TRUE.
...: arguments to be passed to plot.

Author

John Fox jfox@mcmaster.ca

Examples

Run this code

if (require(car)){
    data(Moore)
    with(Moore, plotMeans(conformity, fcategory, partner.status, ylim=c(0, 25)))
}