plot.profile.nls {stats} | R Documentation |
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 nls
and profiled with
profile.nls
.
## S3 method for class 'profile.nls'
plot(x, levels, conf = c(99, 95, 90, 80, 50)/100,
absVal = TRUE, ylab = NULL, lty = 2, ...)
x |
an object of class |
levels |
levels, on the scale of the absolute value of a t
statistic, at which to interpolate intervals. Usually |
conf |
a numeric vector of confidence levels for profile-based
confidence intervals on the parameters.
Defaults to |
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 |
lty |
the line type to be used for axis and dropped lines. |
ylab, ... |
other arguments to the |
The plots are produced in a set of hard-coded colours, but as these
are coded by number their effect can be changed by setting the
palette
. Colour 1 is used for the axes and 4 for the
profile itself. Colours 3 and 6 are used for the axis line at zero and
the horizontal/vertical lines dropping to the axes.
Douglas M. Bates and Saikat DebRoy
Bates, D.M. and Watts, D.G. (1988), Nonlinear Regression Analysis and Its Applications, Wiley (chapter 6)
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, alphamax = 0.05)
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)