23 lines
795 B
R
23 lines
795 B
R
## stepAIC on an lme object: an example from Robert Cuffe
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if(require(nlme)) {
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library(MASS)
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set.seed(321) # to be sure
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a <- data.frame( resp=rnorm(250), cov1=rnorm(250),
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cov2=rnorm(250), group=rep(letters[1:10],25) )
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mod1 <- lme(resp~cov1, a, ~cov1|group, method="ML")
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mod2 <- stepAIC(mod1, scope=list(upper=~(cov1+cov2)^2, lower=~1) )
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beav <- beav2
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set.seed(123)
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beav$dummy <- rnorm(nrow(beav))
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beav.gls <- gls(temp ~ activ + dummy, data = beav,
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correlation = corAR1(0.8), method = "ML")
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stepAIC(beav.gls)
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## for future terms-based nlme
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FIT <- glmmPQL(y ~ trt + I(week > 2), random = ~ 1 | ID,
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family = binomial, data = bacteria)
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form <- formula(FIT)
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stopifnot(form[[2]] == "y")
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}
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