[R] some question about partial prediction in survival
coldeyes.Rhelp
coldeyes.rhelp at gmail.com
Mon Oct 15 05:10:53 CEST 2007
Hi there:
i got a problem to get the prediction from a model recently. for
example if i use a survival analysis to predict the risk. i use the code
like below: i found the the prediction is not equal to (coef * x + coef
* sex) , could someone help me with why this happened? and can someone
explain to me how this command "predict(f, type="terms")" works? is
every partial prediction equal to coef*x=predict(f,type="terms")[,1] and
coef*sex=predict(f,type="terms")[,2]? it looks like they did not match.
however
"predict(f)=predict(f,type="terms")[,1]+predict(f,type="terms")[,2]"
how should i understand this. thanks so much for your help
test1 <- list(time= c(4, 1,1,2,2,3),
status=c(1,1,0,1,1,0),
x= c(0,1,1,1,0,0),
sex= c(0,0,0,1,1,1))
f<-coxph( Surv(time, status) ~ x + sex, test1)
Call:
coxph(formula = Surv(time, status) ~ x + sex, data = test1)
coef exp(coef) se(coef) z p
x 1.713 5.546 1.34 1.282 0.20
sex -0.154 0.857 1.45 -0.106 0.92
Likelihood ratio test=1.85 on 2 df, p=0.397 n= 6
bests;
T.D
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