I am trying to estimate survival of fishes exposed to multiple
concentrations of a contaminant. Only fishes exposed to the highest
concentration experienced high mortality. Consequently, most of the
records in my file are censored data at the last day of the experiment.
The analysis,
se3.surv <- survfit(Surv(time, cens) ~ treat, data = se3t)
results in an error message: "Problem: No. of rows in Surv(time, cens)
(variable 1) is 798 != length of others (364)"
Records on the last day start on row 365. I get no error message when
data from the last day is excluded, but then most n.risk values, and
survival estimates, are wrong.
I would appreciate suggestions,
thanks
S-Plus 6.2 for Windows (Professional Edition)
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