Consider the following AML – acute myelogenous leukemia data. The study was conducted by Embury et al. (1977) at Stanford University.

Group	Length of complete remission (in weeks)
Maintained	9,13,13+,18,23,28+,31,34,45+,48,161+
Nonmaintained	5,5,8,8,12,16+,23,27,30,33,43,45

1. Produce tables for KM estimates to each group. Then plot KM curves for each roup on the same graph. Comment on how these curves compare with each other.
2. Use R to check your answers.
3. Use (i) the Gehan’s Generalised Wilcoxon Test (ii) the Cox-Mantel Test and (iii) the logrank test to compare two survival curves in part (a). What is your null hypothesis and how is the test statistic distributed under this null hypothesis? What are your conclusions from the test?
4. Use excel and R to check your results.