Hello,
i'm tring to use a cox's model for a survival analysis. I have a
dataset,
this is a part:
VOD SESSO fonte_sct donor RT_CGY STATOBMT TEMPO morto
1 0 F mid related 1200
CP 65 1
2 0 M mid 1200
2RC 5281 0
3 0 M mid unrelated 1200 1RC
218 0
4 0 M per unrelated 1200 2RC
484 0
5 0 F mid 1200
1RC 302 1
6 0 M mid related 1200 1RC
1235 0
but when i try this command i have a warning:
> fit = coxph( Surv(TEMPO,morto==1)~ VOD + SESSO + fonte_sct + donor +
RT_CGY + STATOBMT)
Warning message:
In coxph(Surv(TEMPO, morto == 1) ~ VOD + SESSO + fonte_sct + donor + :
X matrix deemed to be singular; variable 10 14 15 18 20 21 22 24 25 26
why??? anyone know the solution of this??
Thanks
Michele
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