av.plots
From car v1.2-10
by John Fox
Added-Variable Plots
These functions construct added-variable (also called partial-regression) plots for linear and generalized linear models.
- Keywords
- hplot, regression
Usage
av.plots(model, variable, ask=missing(variable), one.page=!ask, ...)
avp(...)
av.plot(model, ...)
## S3 method for class 'lm':
av.plot(model, variable,
labels=names(residuals(model)[!is.na(residuals(model))]),
identify.points=TRUE, las=par("las"), col=palette()[2], pch=1, lwd=2,
main="Added-Variable Plot", ...)
## S3 method for class 'glm':
av.plot(model, variable,
labels=names(residuals(model)[!is.na(residuals(model))]),
identify.points=TRUE, las=par("las"), col=palette()[2], pch=1, lwd=2,
main="Added-Variable Plot", type=c("Wang", "Weisberg"), ...)
Arguments
- model
- model object produced by
lm
orglm
. - variable
- variable (if it exists in the search path) or
name of variable. This argument usually is omitted for
avp
orav.plots
. - ask
- if
TRUE
, a menu is provided in the R Console for the user to select the term(s) to plot. - one.page
- if
TRUE
(andask=FALSE
), put all plots on one graph. - labels
- observation names.
- identify.points
- if
TRUE
, then identify points interactively. - las
- if
0
, ticks labels are drawn parallel to the axis; set to1
for horizontal labels (seepar
). - col
- color for points and lines; the default is the second entry
in the current color palette (see
palette
andpar
). - pch
- plotting character for points; default is
1
(a circle, seepar
). - lwd
- line width; default is
2
(seepar
). - main
- title for plot.
- type
- if
"Wang"
use the method of Wang (1985); if"Weisberg"
use the method in the Arc software associated with Cook and Weisberg (1999). - ...
- arguments to be passed down to
av.plot.lm
orav.plot.glm
.
Details
The function intended for direct use is av.plots
(for which avp
is an abbreviation). By default, these functions are used interactively
through a text menu.
The model can contain factors and interactions. An added-variable plot can be
drawn for each column of the model matrix, including the constant.
Value
NULL
. These functions are used for their side effect: producing plots.
References
Cook, R. D. and Weisberg, S. (1999) Applied Regression, Including Computing and Graphics. Wiley. Fox, J. (1997) Applied Regression, Linear Models, and Related Methods. Sage. Wang, P C. (1985) Adding a variable in generalized linear models. Technometrics 27, 273--276.
See Also
Examples
av.plots(lm(prestige~income+education+type, data=Duncan))
av.plots(glm(partic != "not.work" ~ hincome + children,
data=Womenlf, family=binomial))
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