\HeaderA{plot.profile.nls}{Plot a profile.nls Object}{plot.profile.nls}
\keyword{nonlinear}{plot.profile.nls}
\keyword{regression}{plot.profile.nls}
\keyword{models}{plot.profile.nls}
\begin{Description}\relax
Displays a series of plots of the profile t function and interpolated
confidence intervals for the parameters in a nonlinear regression
model that has been fit with \code{nls} and profiled with
\code{profile.nls}.
\end{Description}
\begin{Usage}
\begin{verbatim}
## S3 method for class 'profile.nls':
plot(x, levels, conf= c(99, 95, 90, 80, 50)/100,
     nseg = 50, absVal =TRUE, ...)
\end{verbatim}
\end{Usage}
\begin{Arguments}
\begin{ldescription}
\item[\code{x}] an object of class \code{"profile.nls"} 
\item[\code{levels}] levels, on the scale of the absolute value of a t
statistic, at which to interpolate intervals.  Usually \code{conf}
is used instead of giving \code{levels} explicitly.
\item[\code{conf}] a numeric vector of confidence levels for profile-based
confidence intervals on the parameters.  Defaults to \code{c(0.99,
         0.95, 0.90, 0.80, 0.50).}
\item[\code{nseg}] an integer value giving the number of segments to use in
the spline interpolation of the profile t curves. Defaults to 50.
\item[\code{absVal}] a logical value indicating whether or not the plots
should be on the scale of the absolute value of the profile t.
Defaults to \code{TRUE}.
\item[\code{...}] other arguments to the \code{plot} function can be passed here.
\end{ldescription}
\end{Arguments}
\begin{Author}\relax
Douglas M. Bates and Saikat DebRoy
\end{Author}
\begin{References}\relax
Bates, D.M. and Watts, D.G. (1988),
\emph{Nonlinear Regression Analysis and Its Applications},
Wiley (chapter 6)
\end{References}
\begin{SeeAlso}\relax
\code{\LinkA{nls}{nls}},
\code{\LinkA{profile}{profile}},
\code{\LinkA{profile.nls}{profile.nls}}
\end{SeeAlso}
\begin{Examples}
\begin{ExampleCode}
require(graphics)

# obtain the fitted object
fm1 <- nls(demand ~ SSasympOrig( Time, A, lrc ), data = BOD)
# get the profile for the fitted model
pr1 <- profile( fm1 )
opar <- par(mfrow = c(2,2), oma = c(1.1, 0, 1.1, 0), las = 1)
plot(pr1, conf = c(95, 90, 80, 50)/100)
plot(pr1, conf = c(95, 90, 80, 50)/100, absVal = FALSE)
mtext("Confidence intervals based on the profile sum of squares",
      side = 3, outer = TRUE)
mtext("BOD data - confidence levels of 50%, 80%, 90% and 95%",
      side = 1, outer = TRUE)
par(opar)
\end{ExampleCode}
\end{Examples}

