---
data_dictionary: rats.csv

  
description: >
  This dataset shows survival times for rats 
  provided an unspecified medical treatment 
  or a placebo. The experiment randomized three
  pups within an individual litter, one to the
  treatment group and two to the control group.
  This data is useful for (among other things)
  showing how to account for a litter effect
  in a Cox proportional hazards model.
  
copyright:
  https://www.r-project.org/Licenses/

source: >
  Therneau T (2020). A Package for Survival 
  Analysis in R. R package version 3.1-12, 
  CRAN.R-project.org/package=survival.

  Terry M. Therneau, Patricia M. Grambsch (2000).
  Modeling Survival Data, Extending the Cox Model.
  Springer, New York. ISBN 0-387-98784-3.

  D.F. Andrews and A.M. Herzberg (1985). Data.

format: 
  comma-delimited

varnames: 
  first row of data

missing_value_code:
  not needed
  
size:
  rows: 300
  columns: 5

vars:
  litter:
    label: consecutive numbers from 1 to 100 identifying specific litters

  rx:
    label: indicator variable for treatment
    value:
      placebo: 0
      treatment: 1
      
  time:
    label: time until survival or censoring
    unit: days
    
  status:
    label: code for death
    value:
      alive at last evalation (censored): 0
      died: 1
  
  sex:
    label: sex
    value:
      female: f
      male: m
---