format
A data frame containing:
ll{
trt treatment: 1=standard 2=test
celltype cell-type: 1=squamous, 2=smallcell, 3=adeno, 4=large
time survival time
status censoring status
karno Karnofsky performance score (100=good)
diagtime months from diagnosis to randomisation
age age in years
prior prior therapy 0=no, 1=yes
}source
Kalbfleisch and Prentice, The Statistical
Analysis of Failure Time Data.