Compare Likelihoods of Fitted Objects

Usage

anova(object, ..., test, verbose)

Arguments

object a fitted model object inheriting from class lme or class gls.
... other optional fitted model objects inheriting from classes gls, lm, lme, or lmList.
test an optional logical value controlling whether likelihood ratio tests should be used to compare the fitted models represented by object and the objects in .... Defaults to TRUE.
verbose an optional logical value. If TRUE, the calling sequences for each fitted model object are printed with the rest of the output, being omitted if verbose = FALSE. Defaults to FALSE.

Description

When only one fitted model object is present, a data frame with the estimated values, the approximate standard errors, the z-ratios, and the p-values for the fixed effects is returned. Otherwise, when multiple fitted objects are being compared, a data frame with the degrees of freedom, the (restricted) log-likelihood, the Akaike Information Criterion (AIC), and the Bayesian Information Criterion (BIC) of each object is returned. If test=TRUE, whenever two consecutive objects have different number of degrees of freedom, a likelihood ratio statistic, with the associated p-value is included in the returned data frame.

Value

a data frame inheriting from class anova.lme.

Note

Likelihood comparisons are not meaningful for objects fit using restricted maximum likelihood and with different fixed effects.

Author(s)

Jose Pinheiro and Douglas Bates

See Also

gls, lme, AIC, BIC, print.anova.lme

Examples

library(lme)
data(Orthodont)
fm1 <- lme(distance ~ age, Orthodont, random = ~ age | Subject)
fm2 <- update(fm1, distance ~ age * Sex)
anova(fm1, fm2)


[Package Contents]