###### Nonparametric methods################
library(survival)
library(MASS)
ovarian  ###Ovarian Cancer Survival Data###
attach(ovarian)

##KM estimate survival curve####
non1=survfit(Surv(futime, fustat)~1,data=ovarian)
non2=survfit(Surv(futime, fustat)~rx,data=ovarian)
plot(non1)
plot(non2,lty=1:2)
##NA estimate survival curve#
non1b=survfit(Surv(futime, fustat)~1,ctype=1, data=ovarian)
non2b=survfit(Surv(futime, fustat)~rx,ctype=1,data=ovarian)

plot(non1b)
plot(non2b,lty=1:2)

######log rank test############

dif1=survdiff(Surv(futime, fustat)~rx,data=ovarian)
dif1