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Unformatted text preview: 412 0.2002 Parameter Null hypothesis of test for interaction: hazards are proportional.
No evidence against proportional hazards. 23 Stomach Cancer Breast Cancer 24 In the stomach cancer example, time is years proc PHreg data=pubh.stomach_cancer ; model years*censor(1) = group group_time / risklimits ties=efron;
group_time = group * years; Variable
group_time 1 Parameter
Estimate 1 Standard
0.78008 DF 0.39591
0.27731 Chi-Square Pr > ChiSq 7.9752
0.0049 Interaction is highly signiﬁcant, strong evidence against proportional hazards. 25 Time-varying predictor: Alport mice example Compare survival of two groups of mice (“offspring 129” and “French”) with a
genetic kidney disease.
Kidney function measured from urine at 2, 4, and 6 months after birth.
All mice who survived to 6 months censored.
Need a predictor that changes at 2, 4, and 6 months, like time-varying predictor in
the test for non-proportional hazard. 26 Proc PHreg data= Alport;
class group ;
model surv_days*early_death(0) =...
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This note was uploaded on 11/21/2011 for the course PUBH 6470 taught by Professor Williamthomas during the Fall '11 term at University of Florida.
- Fall '11