/* PubH 7450
Exampel 4.1d: Confidence bands of a survival curve 
*/

options ls=80 center pagesize=60 number label;

data cancer;
infile '/home/merganser/weip/public_html/course/7450/data/leukemia.dat' 
       firstobs=2;
input group $ weeks relaps ;

data grp6MP;
  set cancer;
  if group='6-MP';

/* obtain 95% log-transformed confidence bands: 
   conftype=ASINSQRT or LOGLOG or LINEAR or LOG or LOGIT;
   confband=EP or HW or ALL;
   bandmin, bandmax: time interval for confidence band;
   out: SAS output dataset.
   see http://support.sas.com/onlinedoc/913/docMainpage.jsp
*/

proc lifetest method=km data=grp6MP ;
by group;
time weeks*relaps(0) ;
survival conftype=log confband=HW bandmin=0 bandmax=20 out=a;

proc print data=a;

run;

**************************************

   Obs group weeks _CENSOR_ SURVIVAL CONFTYPE SDF_LCL SDF_UCL  HW_LCL  HW_UCL

     1 6-MP     0      .     1.00000          1.00000 1.00000 0.76858 1.00000
     2 6-MP     6      0     0.85714   LOG    0.71982 1.00000 0.63050 1.00000
     3 6-MP     6      1     0.85714           .       .       .       .     
     4 6-MP     7      0     0.80672   LOG    0.65312 0.99644 0.58148 1.00000
     5 6-MP     9      1     0.80672           .       .       .       .     
     6 6-MP    10      0     0.75294   LOG    0.58592 0.96757 0.52861 1.00000
     7 6-MP    10      1     0.75294           .       .       .       .     
     8 6-MP    11      1     0.75294           .       .       .       .     
     9 6-MP    13      0     0.69020   LOG    0.50961 0.93477 0.46469 1.00000
    10 6-MP    16      0     0.62745   LOG    0.43939 0.89599 0.40174 0.97997
    11 6-MP    17      1     0.62745           .       .       .       .     
    12 6-MP    19      1     0.62745           .       .       .       .     
    13 6-MP    20      1     0.62745           .       .       .       .     
    14 6-MP    22      0     0.53782   LOG    0.33704 0.85820  .       .     
    15 6-MP    23      0     0.44818   LOG    0.24879 0.80737  .       .     
    16 6-MP    25      1      .                .       .       .       .     
    17 6-MP    32      1      .                .       .       .       .     
    18 6-MP    32      1      .                .       .       .       .     
    19 6-MP    34      1      .                .       .       .       .     
    20 6-MP    35      1      .                .       .       .       .