Calculate a hazard ratio and CI for a 5-year increase in age by computing the fifth power of the estimated hazard ratio and its confidence limits, using the results for a 1-year increase in Table 6.9....

Calculate a hazard ratio and CI for a 5-year increase in age by computing the fifth power of the estimated hazard ratio and its confidence limits, using the results for a 1-year increase in Table 6.9. Compare the result to a fit of the Cox model using a re-scaled version of the variable.