R-help to exercise 24

           

 

# Read the data into a dataframe:

melanom=read.table("http://www.uio.no/studier/emner/matnat/math/STK4900/data/melanoma.txt",header=T)

 

# Attach the R-library for survival analysis (if you have not already done so):

library(survival)

 

 

# QUESTION a

 

# Commands:

fit.sex=survfit(Surv(lifetime,status==1)~sex, data=melanom)

plot(fit.sex, lty=1:2, mark.time=F)

survdiff(Surv(lifetime,status==1)~sex, data=melanom)

 

 

# QUESTIONS b and c are done by similar commands

 

 

# QUESTIONS d and e

 

# Commands for sex

coxfit.sex=coxph(Surv(lifetime,status==1)~factor(sex),data=melanom)

summary(coxfit.sex)

 

# The other covariates in question d are done by similar commands, and so is question e