The R Project SVN R

\name{termplot}

\alias{termplot}

\title{Plot regression terms}

\description{

  Plots regression terms against their predictors, optionally with

  standard errors and partial residuals added.

}

\usage{

termplot(model, data=NULL, envir=environment(formula(model)),

         partial.resid=FALSE, rug=FALSE,

         terms=NULL, se=FALSE, xlabs=NULL, ylabs=NULL, main = NULL,

         col.term = 2, lwd.term = 1.5,

         col.se = "orange", lty.se = 2, lwd.se = 1,

         col.res = "gray", cex = 1, pch = par("pch"),

         col.smth = "darkred", lty.smth=2, span.smth=2/3,

         ask = interactive() && nb.fig < n.tms && .Device !="postscript",

         use.factor.levels=TRUE, smooth=NULL,

         \dots)

}

\arguments{

  \item{model}{fitted model object}

  \item{data}{data frame in which variables in \code{model} can be

    found}

  \item{envir}{environment in which variables in \code{model} can be found}

  \item{partial.resid}{logical; should partial residuals be plotted?}

  \item{rug}{add \link{rug}plots (jittered 1-d histograms) to the axes?}

  \item{terms}{which terms to plot (default \code{NULL} means all terms)}

  \item{se}{plot pointwise standard errors?}

  \item{xlabs}{vector of labels for the x axes}

  \item{ylabs}{vector of labels for the y axes}

  \item{main}{logical, or vector of main titles;  if \code{TRUE}, the

    model's call is taken as main title, \code{NULL} or \code{FALSE} mean

    no titles.}

  \item{col.term, lwd.term}{color and line width for the \dQuote{term curve},

    see \code{\link{lines}}.}

  \item{col.se, lty.se, lwd.se}{color, line type and line width for the

    \dQuote{twice-standard-error curve} when \code{se = TRUE}.}

  \item{col.res, cex, pch}{color, plotting character expansion and type

    for partial residuals, when \code{partial.resid = TRUE}, see

    \code{\link{points}}.}

   \item{ask}{logical; if \code{TRUE}, the user is \emph{ask}ed before

     each plot, see \code{\link{par}(ask=.)}.}

   \item{use.factor.levels}{Should x-axis ticks use factor levels or

     numbers for factor terms?}

   \item{smooth}{\code{NULL} or a function with the same arguments as

     \code{\link{panel.smooth}} to draw a smooth through the partial

     residuals for non-factor terms}

   \item{lty.smth,col.smth, span.smth}{Passed to \code{smooth}}

  \item{\dots}{other graphical parameters}

}

\details{

  The model object must have a \code{predict} method that accepts

  \code{type=terms}, eg \code{\link{glm}} in the \pkg{base} package,

  \code{\link[survival]{coxph}} and \code{\link[survival]{survreg}} in

  the \pkg{survival} package.

  For the \code{partial.resid=TRUE} option it must have a

  \code{\link{residuals}} method that accepts \code{type="partial"},

  which \code{\link{lm}} and \code{\link{glm}} do.

  The \code{data} argument should rarely be needed, but in some cases

  \code{termplot} may be unable to reconstruct the original data frame.

  Nothing sensible happens for interaction terms.

}

\seealso{For (generalized) linear models, \code{\link{plot.lm}} and

  \code{\link{predict.glm}}.}

\examples{

had.splines <- "package:splines" \%in\% search()

if(!had.splines) rs <- require(splines)

x <- 1:100

z <- factor(rep(LETTERS[1:4],25))

y <- rnorm(100,sin(x/10)+as.numeric(z))

model <- glm(y ~ ns(x,6) + z)

par(mfrow=c(2,2)) ## 2 x 2 plots for same model :

termplot(model, main = paste("termplot( ", deparse(model$call)," ...)"))

termplot(model, rug=TRUE)

termplot(model, partial=TRUE, se = TRUE, main = TRUE)

termplot(model, partial=TRUE, smooth=panel.smooth,span.smth=1/4)

if(!had.splines && rs) detach("package:splines")

}

\keyword{hplot}

\keyword{regression}