tlumley at u.washington.edu
Wed Jan 25 20:59:10 CET 2006
On Wed, 25 Jan 2006, singyee ling wrote:
> Dear R-users,
> I am sorry if this is obvious. I am testing the proportional hazard
> assumptions using cox.zph. If i am not wrong, a g(t) function must be
> assumed. Four possibilities available in R are "km","identity" and "rank".
> may i know what functions of time are these transformation assuming?
It should be fairly clear what "identity", "log" and "rank" are:
and the rank of the observations time, respectively.
"km" uses the Kaplan-Meier estimator of survival at time t.
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