2. Repeat problem I using WHAS500 data. All calculations for this problem should be done using a software package. 3. Repeat problem I using the WHAS500 data with four groups defined by the age intervals: [40-591, [60, 691, 170, 79] and [80,901. 4. Compute by hand, and verify hand calculations with a software package, the log- rank, generalized Wilcoxon, and Peto-Prentice tests for the equality of the two survival functions estimated in problem I(a). 5. Repeat problem 4 using data from the WHAS500 data in problem 2