profile.nls

0th

Percentile

Method for Profiling nls Objects

Investigates the profile log-likelihood function for a fitted model of class "nls".

Keywords
models, regression, nonlinear
Usage
# S3 method for nls
profile(fitted, which = 1:npar, maxpts = 100, alphamax = 0.01,
        delta.t = cutoff/5, …)
Arguments
fitted

the original fitted model object.

which

the original model parameters which should be profiled. This can be a numeric or character vector. By default, all non-linear parameters are profiled.

maxpts

maximum number of points to be used for profiling each parameter.

alphamax

highest significance level allowed for the profile t-statistics.

delta.t

suggested change on the scale of the profile t-statistics. Default value chosen to allow profiling at about 10 parameter values.

further arguments passed to or from other methods.

Details

The profile t-statistics is defined as the square root of change in sum-of-squares divided by residual standard error with an appropriate sign.

Value

A list with an element for each parameter being profiled. The elements are data-frames with two variables

par.vals

a matrix of parameter values for each fitted model.

tau

the profile t-statistics.

References

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

See Also

nls, profile, plot.profile.nls

Aliases
  • profile.nls
Examples
library(stats) # NOT RUN { # obtain the fitted object fm1 <- nls(demand ~ SSasympOrig(Time, A, lrc), data = BOD) # get the profile for the fitted model: default level is too extreme pr1 <- profile(fm1, alpha = 0.05) # profiled values for the two parameters pr1$A pr1$lrc # see also example(plot.profile.nls) # }
Documentation reproduced from package stats, version 3.5.0, License: Part of R 3.5.0

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