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R version 2.9.0 (2009-04-17)
Copyright (C) 2009 The R Foundation for Statistical Computing
ISBN 3-900051-07-0
R is free software and comes with ABSOLUTELY NO WARRANTY.
You are welcome to redistribute it under certain conditions.
Type 'license()' or 'licence()' for distribution details.
R is a collaborative project with many contributors.
Type 'contributors()' for more information and
'citation()' on how to cite R or R packages in publications.
Type 'demo()' for some demos, 'help()' for on-line help, or
'help.start()' for an HTML browser interface to help.
Type 'q()' to quit R.
> #
> # Test out anova, with strata terms
> #
> options(na.action=na.omit)
> library(survival)
Loading required package: splines
>
> fit1 <- coxph(Surv(time, status) ~ ph.ecog + wt.loss + strata(sex) +
+ poly(age,3), lung)
> ztemp <- anova(fit1)
>
> tdata <- na.omit(lung[, c('time', 'status', 'ph.ecog', 'wt.loss', 'sex', 'age')])
> fit2 <- coxph(Surv(time, status)~ ph.ecog + wt.loss + poly(age,3) + strata(sex),
+ data=tdata)
> ztemp2 <- anova(fit2)
> all.equal(ztemp, ztemp2)
[1] TRUE
>
>
> fit2 <- coxph(Surv(time, status) ~ ph.ecog + wt.loss + strata(sex), tdata)
> fit3 <- coxph(Surv(time, status) ~ ph.ecog + strata(sex), tdata)
>
> all.equal(ztemp$loglik, c(fit1$loglik[1], fit3$loglik[2], fit2$loglik[2],
+ fit1$loglik[2]))
[1] TRUE
> all.equal(ztemp$Chisq[-1], 2* diff(ztemp$loglik))
[1] TRUE
> all.equal(ztemp$Df[-1], c(1,1,3))
[1] TRUE
>
> ztemp2 <- anova(fit3, fit2, fit1)
> all.equal(ztemp2$loglik, ztemp$loglik[-1])
[1] TRUE
> all.equal(ztemp2$Chisq[2:3], ztemp$Chisq[3:4])
[1] TRUE
> all.equal(ztemp2$P[2:3], ztemp$P[3:4])
[1] TRUE
>
>
>
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