swh:1:snp:13ceaf33a0cf03b54a9c83ec2c853f3c4226f6da
Tip revision: db71ff249d1c39fbfe9c8c7013b9a7fb82eb36c9 authored by Ben Bolker on 15 November 2007, 00:00:00 UTC
version 0.8.2
version 0.8.2
Tip revision: db71ff2
BIC-methods.Rd
\name{BIC-methods}
\docType{methods}
\alias{BIC}
\alias{BIC-methods}
\alias{AIC-methods}
\alias{AICc-methods}
\alias{logLik-methods}
\alias{AICc}
\alias{AIC,mle2-method}
\alias{AICc,mle2-method}
\alias{AICc,logLik-method}
\alias{AICc,ANY-method}
\alias{AICc,ANY,mle2,logLik-method}
\alias{BIC,logLik-method}
\alias{BIC,ANY-method}
\alias{BIC,mle2-method}
\alias{BIC,ANY,mle2,logLik-method}
\alias{logLik,mle2-method}
\alias{anova,mle2-method}
\title{Log likelihoods and model selection for mle2 objects}
\description{
Various functions for likelihood-based and information-theoretic
model selection of likelihood models
}
\section{Methods}{
\describe{
\item{logLik}{\code{signature(object = "mle2")}: Extract maximized
log-likelihood.}
\item{AIC}{\code{signature(object = "mle2")}: Calculate
Akaike Information Criterion}
\item{AICc}{\code{signature(object = "mle2")}: Calculate
small-sample corrected Akaike Information Criterion}
\item{BIC}{\code{signature(object = "mle2")}: Calculate
Bayesian (Schwarz) Information Criterion}
\item{BIC}{\code{signature(object = "logLik")}: Calculate
Bayesian (Schwarz) Information Criterion}
\item{BIC}{\code{signature(object = "ANY")}: Calculate
Bayesian (Schwarz) Information Criterion}
\item{anova}{\code{signature(object="mle2")}: Likelihood Ratio Test
comparision of different models}
}
}
\usage{
\S4method{BIC}{ANY,mle2,logLik}(object,...)
}
\arguments{
\item{object}{A \code{logLik} or \code{mle2} object}
\item{...}{An optional list of additional \code{logLik}
or \code{mle2} objects (fitted to the same data set).
If the number of attributes has not been included as an attribute of
the fit or of the log-likelihood, it can specified as
\code{nobs=} in this list.}
}
\details{
Further arguments to \code{BIC} can be specified
in the \code{...} list: \code{delta} (logical)
specifies whether to include a column for delta-BIC
in the output.
}
\value{
A table of the BIC values, degrees of freedom,
and possibly delta-BIC values relative to the
minimum-BIC model
}
\note{This is implemented in an ugly way and could
probably be improved!}
\examples{
x <- 0:10
y <- c(26, 17, 13, 12, 20, 5, 9, 8, 5, 4, 8)
(fit <- mle2(y~dpois(lambda=ymax/(1+x/xhalf)),
start=list(ymax=25,xhalf=3)))
(fit2 <- mle2(y~dpois(lambda=(x+1)*slope),
start=list(slope=1)))
BIC(fit,nobs=length(x))
BIC(fit,fit2,nobs=length(x))
}
\keyword{methods}