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. [New England Journal of Medicine, 337 (1997), 295–300], and answer the following questions:

(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?