cap log close
clear
log using StataLog, replace 

include "http://192.38.117.59/~linearpredictors/datafiles/readPbc3.do"

xtile biligroup = bili, nq(5)
egen biliQuintileMeans = mean(bili), by(biligroup)
label variable biliQuintileMeans "Mean level of bilirubin within quintile groups"

/* Size of quintile groups, and groupwise means */
table biliQuintileMeans

/* Declare data to be survival-time data */
quietly stset followup, failure(status == 1 2) 

/* Observed and expected no of failures */
xi: sts test i.biligroup

log close