I would like to determine whether there's a difference between survival data for two groups.
I have been using the survival package and survdiff() with rho=0 and rho=1. Survdiff() with rho=0 is a non-continuity-corrected version of the log-rank test set forth in "Fundamentals of Biostatistics" by Bernard Rosner. On page 722 of the 5th edition, Rosner states, "This test should be used only if Var_LR >= 5." For my data with rho=0 or rho=1, survdiff()$var[1,1] is much less than 5. Can anyone suggest what to do in this case? Also, can anyone suggest a reference or software for doing power calculations regarding tests for difference between survival data for two groups. Thanks very much. -Ben ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
