Consider two individuals (individual 1 and individual 2) with covariates and assume that the hazard rates of their survival times are given by Cox’s regression model (1.6): a) Show that the hazard...

Consider two individuals (individual 1 and individual 2) with covariates

and assume that the hazard rates of their survival times are given by Cox’s regression model (1.6):

a) Show that the hazard ratio α₂(t)/α1(t) does not depend on time t, that is, that the hazards are proportional.

b) Determine the hazard ratio α₂(t)/α1(t) for the special case where

for all

Use the result to give an interpretation of the quantities