[R] Cox Proportional Hazards
Nanthinee Jeevanandam
nanthineej at gmail.com
Tue Aug 21 12:40:01 CEST 2012
I have run this model for my data set on insect survival time for
different temperature treatments in R. I understand the Wald statistic
reports on whether the variable
makes a difference to the model but there is also a p-value so i am
not sure whther to report the Wald statistic. I have pasted a copy of
my result below. Humidity is categorical (a & b) while temperature is
continuous.
coxph(formula = Surv(time, death) ~ Humidity + temp)
n= 1504, number of events= 1504
coef exp(coef) se(coef) z Pr(>|z|)
Hum.b -0.03023 0.97022 0.05695 -0.531 0.595
temp 1.19094 3.29017 0.03360 35.444 <2e-16 ***
---
Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
exp(coef) exp(-coef) lower .95 upper .95
Humb 0.9702 1.0307 0.8678 1.085
temp 3.2902 0.3039 3.0805 3.514
Concordance= 0.918 (se = 0.013 )
Rsquare= 0.742 (max possible= 1 )
Likelihood ratio test= 2036 on 2 df, p=0
Wald test = 1281 on 2 df, p=0
Score (logrank) test = 1948 on 2 df, p=0
How do I interpret the Wald test in this case? Really appreciate the help.
nj
More information about the R-help
mailing list