How do i do the second question? How do i input the data? I have to code in R studio. How should i go about doing this question?

2. A study was performed to compare three treatments in treating a certain tumor. Three groups of rats were studied. One group went untreated, another was treated only with radiation, and the third group received radiation plus an appropriate concentration of BPA. The data for the three groups lists the death times (in days) and is given below: Untreated Radiated Radiated+BPA 20 26 31 21 28 32 23 20 34 24 29 35 24 30 36 26 30 38 26 31 3827 31 39 28 32 42+ 30 35+ 42+ i) Perform a log-rank test for the three samples to determine if there is any difference in survival among groups. ii) If there is a prior evidence that if there is a difference in survival, there should be a natural ordering, namely, untreated animals will have the worst survival, radiated rats will have slightly improved survival, and the radiated rats+BPA should have the best survival. Would you test this ordered hypothesis by using the pairwise tests? How