Estimating Cox Model parameters with and without coxph function from survival package

Reading data


library(survival)
data(veteran)
time.var <- veteran[,3] 
status.var <- veteran[,4] 
covariate.matrix <- veteran[,c(1,5:8)] 
covariate.names <- names(veteran[,c(1,5:8)])
data <- cbind.data.frame(time.var,status.var,covariate.matrix)

Kaplan-Meier and Nelson-Aalen estimates with and without survfit function from survival package

Data reading:


rm(list=ls(all=TRUE)) # wipe out everything else
require(survival)
data = aml[aml$x == "Maintained",]
data

Biostatistics and R

Biostatistics is mainly statistics for clinical and epidemiological studies that studies the occurrence of illness (morbidity), death (mortality) in a point of time or in a course of time and finds various models and estimates of risks (probability of that event occurrence).