plot.design {graphics}R Documentation

Plot Univariate Effects of a Design or Model

Description

Plot univariate effects of one or more factors, typically for a designed experiment as analyzed by aov().

Usage

plot.design(x, y = NULL, fun = mean, data = NULL, ...,
            ylim = NULL, xlab = "Factors", ylab = NULL,
            main = NULL, ask = NULL, xaxt = par("xaxt"),
            axes = TRUE, xtick = FALSE)

Arguments

x

either a data frame containing the design factors and optionally the response, or a formula or terms object.

y

the response, if not given in x.

fun

a function (or name of one) to be applied to each subset. It must return one number for a numeric (vector) input.

data

data frame containing the variables referenced by x when that is formula-like.

...

graphical parameters such as col, see par.

ylim

range of y values, as in plot.default.

xlab

x axis label, see title.

ylab

y axis label with a ‘smart’ default.

main

main title, see title.

ask

logical indicating if the user should be asked before a new page is started – in the case of multiple y values.

xaxt

character giving the type of x axis.

axes

logical indicating if axes should be drawn.

xtick

logical indicating if ticks (one per factor) should be drawn on the x axis.

Details

The supplied function will be called once for each level of each factor in the design and the plot will show these summary values. The levels of a particular factor are shown along a vertical line, and the overall value of fun() for the response is drawn as a horizontal line.

Note

A big effort was taken to make this closely compatible to the S version. However, col (and fg) specifications have different effects.

In S this was a method of the plot generic function for design objects.

Author(s)

Roberto Frisullo and Martin Maechler

References

Chambers J. M., Hastie T. J. (1992). Statistical Models in S. Chapman & Hall, London. ISBN 9780412830402. Pages 546–7 (and 163–4).

Freeny A. E., Landwehr J. M. (1992). “Displays for Data from Large Designed Experiments.” In Page C., LePage R. (eds.), Computing Science and Statistics, 117–126. ISBN 978-1-4612-2856-1. doi:10.1007/978-1-4612-2856-1_15.

See Also

interaction.plot for a ‘standard graphic’ of designed experiments.

Examples

require(stats)
plot.design(warpbreaks)  # automatic for data frame with one numeric var.

Form <- breaks ~ wool + tension
summary(fm1 <- aov(Form, data = warpbreaks))
plot.design(       Form, data = warpbreaks, col = 2)  # same as above

## More than one y :
utils::str(esoph)
plot.design(esoph) ## two plots; if interactive you are "ask"ed

## or rather, compare mean and median:
op <- par(mfcol = 1:2)
plot.design(ncases/ncontrols ~ ., data = esoph, ylim = c(0, 0.8))
plot.design(ncases/ncontrols ~ ., data = esoph, ylim = c(0, 0.8),
            fun = median)
par(op)

[Package graphics version 4.6.0 Index]