log-log KM plot: Male-Female

Question: Assess the log-log KM plot for Sex variable on the remission dataset. Does it satisfy the PH assumption?

Answer:

Load package survival

library(survival)

Load data

data <- read.csv("C:/Users/user/Documents/MATERI KULIAH/TUGAS SEM VI/Ansur/W12/leu3.csv")

Membuat fungsi minusloglog

minusloglog <- function(S) -log(-log(S))

Membuat objek Surv

y <- Surv(time = data$Time, event = data$Censor)

Mengubah kolom “Sex” menjadi faktor dengan label

data$Sex <- factor(data$Sex, levels = c(0, 1), labels = c("Female", "Male")) #asumsi Female = 0 dan Male = 1

Fit model Kaplan-Meier berdasarkan jenis kelamin (Sex)

kmfit_sex <- survfit(y ~ Sex, data = data)

Plot log-log survival untuk Sex

TAMBAHAN : PH Test

### Cox model untuk Sex
cox_model <- coxph(y ~ Sex, data = data)

Uji asumsi PH

cox.zph(cox_model)

##        chisq df       p
## Sex     18.7  1 1.5e-05
## GLOBAL  18.7  1 1.5e-05