On Feb 17, 2010, at 1:54 PM, FishR wrote:
Dear all
I have a dataset examining the probability of a population surviving
(calculated from a logistic regression) of a species over a 200yr
period.
The predictor variables are either continuous but non-normal (e.g.
temperature, oxygen) or categorical (e.g. channelisation),
unfortunately I
also have a large amount of missing values.
Year Decline Temperature Oxygen Channelisation
1800 0.947758115 36.6 NA NA
1801 0.946135961 25.2 NA NA
1802 0.944466388 28.5 NA NA
1803 0.942748196 35.5 NA NA
1804 0.940980166 33 NA NA
1805 0.93916106 30.2 NA NA
truncated …
1999 0.028531339 10.5 NA 5
2000 0.027649801 8.4 NA 5
I have been trying to run a Cox Proportional Hazards Model with the
code
model<-coxph(Surv(Year, Decline) ~ Temperature + Oxygen +
Channelisation)
but keep getting an error message ‘Invalid status value’.
Have I inputted the data in the wrong format or am I trying to run a
totally
unsuitable model?
The second. "Decline" in that coxph model would need to be a two level
variable, factor or integer, "event" or "censored".
You might get further if you described what data you had before you
"logistically" regressed it. (And is this a species of Galapagos
tortoises? I'm trying to figure out the 200 year time scale.)
Any help would be greatly appreciated
Tom
--
David Winsemius, MD
Heritage Laboratories
West Hartford, CT
______________________________________________
R-help@r-project.org mailing list
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.
