equivalent R code to Chen’s Lecture node

R code:

require(survival)
options(contrasts=c('contr.SAS', 'contr.SAS'))

larynx <-  read.table("larynx.data", header=T)
larynx$stage <- as.factor(larynx$stage)

for (i in 2:length(unique(larynx$stage))) {
  tmp1 <- !(larynx$stage == i)
  tmp2 <- !(larynx$stage == (i-1))
  larynx <- cbind(larynx, tmp1, tmp2)
  colnames(larynx)[ncol(larynx)-1] <- paste("Z", i-1, sep='')
  colnames(larynx)[ncol(larynx)] <- paste("stage", i-1, sep='')
}



larynx.survReg1 <- survreg(Surv(stime, censor) ~ Z1 + Z2 + Z3 + age, data=larynx, dist="weibull")

larynx.survReg2 <- survreg(Surv(stime, censor) ~ stage + age, data=larynx, dist="weibull")

larynx.survReg3 <- survreg(Surv(stime, censor) ~ stage1 + stage2 + stage3 + age, data=larynx, dist="weibull")