Load libraries

library(survival) library(survminer)

Load “ovarian” dataset and create a survival object

data(ovarian) surv_obj <- Surv(time = ovarian\(futime, event = ovarian\)fustat)

Kaplan-meier estimation

fit <- survfit(surv_obj ~ rx, data = ovarian) ggsurvplot(fit, data = ovarian, pval = TRUE, conf.int = TRUE, title = “Survival Curves by Treatment Group”, legend.title = “Treatment”)

Long-rank test

survdiff(surv_obj ~ rx, data = ovarian)

Cox Proportional Hazards models

cox_model <- coxph(surv_obj ~ age + resid.ds + rx + ecog.ps, data = ovarian) summary(cox_model)