if available in your library, read the article, '' Improved survival in patients with locally advanced prostate cancer treated with radiotherapy and goserelin," by Michel Bolla et al.

a. How was survival time determined?

b. Why do you think the authors used the log-rank test for comparing the survival curves?

c. Explain the meaning of the p values reported for Figures 1 and 2.

d. What specific statistical results allow the authors to arrive at their stated conclusion?