library(survival)

# Table 3.1, p. 98
# Note: The z test in the table is the score test.  The test labeled likelihood ratio is the 
# partial likelihood test.

age.coxph <- coxph( formula=Surv(time,censor)~age, data=hmohiv, method="breslow", )
print(summary(age.coxph))

# Table 3.2, p. 103
inter.coxph <- coxph( formula=Surv(time,censor)~age+drug+age*drug, data=hmohiv, method="breslow")
print(summary(inter.coxph))

# Note: In order to get the 95% CI for the hazard ratio we could use coxreg instead but then we have to have the predictors 
# all in one matrix or data set.  So, we must create a dataset with just the two predictors and the 
# interaction (called da) in the data set called predictors.  In this function the default for breaking ties is 
# Breslow.

# Table 3.3, p. 105
main.coxph <- coxph( formula=Surv(time,censor)~age+drug, data=hmohiv, method="breslow")
print(summary(main.coxph))

# Table 3.4, p. 108
# Note: SPLUS does have a method="exact" option 
# but it seems to cause problems when we tried to run it.

breslow.coxph <- coxph( formula=Surv(time,censor)~age+drug, data=hmohiv, method="breslow")
print(summary(breslow.coxph))

efron.coxph <- coxph( formula=Surv(time,censor)~age+drug, data=hmohiv)
print(summary(efron.coxph))

#exact.coxph <- coxph( formula=Surv(time,censor)~age+drug, data=hmohiv, method="exact")
#summary(efron.coxph)