car (version 2.0-20)

ceresPlots: Ceres Plots

Description

These functions draw Ceres plots for linear and generalized linear models.

Usage

ceresPlots(model, terms = ~., layout = NULL, ask, main, 
    ...)

ceresPlot(model, ...)

## S3 method for class 'lm':
ceresPlot(model, variable, 
  id.method = list(abs(residuals(model, type="pearson")), "x"),
  labels, 
  id.n = if(id.method[1]=="identify") Inf else 0,
  id.cex=1, id.col=palette()[1],
  line=TRUE, smoother=loessLine, smoother.args=list(),
    smooth, span,
	col=palette()[1], col.lines=palette()[-1],
  xlab, ylab, pch=1, lwd=2,  
  grid=TRUE, ...)

## S3 method for class 'glm':
ceresPlot(model, ...)

Arguments

model

model object produced by lm or glm.

terms

A one-sided formula that specifies a subset of the predictors. One component-plus-residual plot is drawn for each term. The default ~. is to plot against all numeric predictors. For example, the specification terms = ~ . - X3

layout

If set to a value like c(1, 1) or c(4, 3), the layout of the graph will have this many rows and columns. If not set, the program will select an appropriate layout. If the number of graphs exceed nine, you must select the la

ask

If TRUE, ask the user before drawing the next plot; if FALSE, the default, don't ask. This is relevant only if not all the graphs can be drawn in one window.

main

Overall title for any array of cerers plots; if missing a default is provided.

...

ceresPlots passes these arguments to ceresPlot. ceresPlot passes them to plot.

variable

A quoted string giving the name of a variable for the horizontal axis

id.method,labels,id.n,id.cex,id.col

Arguments for the labelling of points. The default is id.n=0 for labeling no points. See showLabels for details of these arguments.

line

TRUE to plot least-squares line.

smoother

Function to add a nonparametric smooth.

smoother.args

see ScatterplotSmoothers for available smooethers and arguments.

smooth, span

these arguments are included for backwards compatility: if smooth=TRUE then smoother is set to loessLine, and if span is specified, it is added to smoother.args.

col

color for points; the default is the first entry in the current color palette (see palette and par).

col.lines

a list of at least two colors. The first color is used for the ls line and the second color is used for the fitted lowess line. To use the same color for both, use, for example, col.lines=c("red", "red")

xlab,ylab

labels for the x and y axes, respectively. If not set appropriate labels are created by the function.

pch

plotting character for points; default is 1 (a circle, see par).

lwd

line width; default is 2 (see par).

grid

If TRUE, the default, a light-gray background grid is put on the graph

Value

• NULL. These functions are used for their side effect: producing plots.

Details

Ceres plots are a generalization of component+residual (partial residual) plots that are less prone to leakage of nonlinearity among the predictors. The function intended for direct use is ceresPlots. The model cannot contain interactions, but can contain factors. Factors may be present in the model, but Ceres plots cannot be drawn for them.

References

Cook, R. D. and Weisberg, S. (1999) Applied Regression, Including Computing and Graphics. Wiley. Fox, J. (2008) Applied Regression Analysis and Generalized Linear Models, Second Edition. Sage. Fox, J. and Weisberg, S. (2011) An R Companion to Applied Regression, Second Edition, Sage. Weisberg, S. (2014) Applied Linear Regression, Fourth Edition, Wiley.

See Also

crPlots, avPlots, showLabels

Examples

ceresPlots(lm(prestige~income+education+type, data=Prestige), terms= ~ . - type)