plot.profile.nls

From stats v3.2.5 by R-core R-core@R-project.org

Plot a profile.nls Object

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.

Keywords: models, regression, nonlinear

Usage

"plot"(x, levels, conf = c(99, 95, 90, 80, 50)/100, absVal = TRUE, ylab = NULL, lty = 2, ...)

Arguments

x: an object of class "profile.nls"
levels: levels, on the scale of the absolute value of a t statistic, at which to interpolate intervals. Usually conf is used instead of giving levels explicitly.
conf: a numeric vector of confidence levels for profile-based confidence intervals on the parameters. Defaults to c(0.99, 0.95, 0.90, 0.80, 0.50).
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 TRUE.
lty: the line type to be used for axis and dropped lines.
ylab, ...: other arguments to the plot.default function can be passed here (but not xlab, xlim, ylim nor type).

Details

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.

References

Bates, D.M. and Watts, D.G. (1988), Nonlinear Regression Analysis and Its Applications, Wiley (chapter 6)

Examples

library(stats)

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, alpha = 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)

Documentation reproduced from package stats, version 3.2.5, License: Part of R 3.2.5

Community examples

Looks like there are no examples yet.