How to note (in code) a few (!) adjusting covariates for cox regression. I had an example for one covariate, and tried (according to my own understanding) two variantes of code (pls, see below), and got ... a different p-value. What is the right code? Many thanks!!!
(1) survdiff (Surv(survt,status)~clinic+strata(prison, dose, gender),data=addicts) N Observed Expected (O-E)^2/E (O-E)^2/V clinic=1 163 122 106.2 2.35 14 clinic=2 75 28 43.8 5.70 14 Chisq= 14 on 1 degrees of freedom, p= 2e-04 (2) survdiff (Surv(survt,status)~clinic+strata(prison+dose+gender),data=addicts) N Observed Expected (O-E)^2/E (O-E)^2/V clinic=1 163 122 106.2 2.35 12.1 clinic=2 75 28 43.8 5.69 12.1 Chisq= 12.1 on 1 degrees of freedom, p= 5e-04 ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
