
Hi guys,

I have been testing the hypothesis for difference of survival between four different classes. The p-values provided in coxph output are confusing for me to interpret.
Here is the output :

sur<-coxph(Surv(SURVIV, status == 1)~factor(A)+cluster(rownames(d)), data = d, model=TRUE)
Call:
coxph(formula = Surv(SURVIV, status == 1) ~ factor(A) + cluster(rownames(d)), data = d, model = TRUE)


            coef exp(coef) se(coef) robust se       z      p
A2 -15.438  1.97e-07 3842.826     1.022 -15.112 0.0000
A3   0.471  1.60e+00    0.615     0.564   0.835 0.3000
A4   1.550  4.71e+00    0.547     0.551   2.811 0.0039

Likelihood ratio test=6.73  on 3 df, p=0.0811  n=171

---
In above result, I can see that overall p-value from LR test is non-significant. But the p-values for two groups(A2 and A4) are significant. 
I have three questions: 

Can anyone help me whether this points to any significant interpretation ?

Is it okay to ignore the overall p-value ?

Please also let me know if you have got some more suggestions to improve the result.

Thanks,
-V







 		 	   		  
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