1. The kidney data set is available in the survival library in R and on GauchoSpace. It measures the time until a recurrent infection was observed in kidney dialysis patients. (a) Plot the KaplaniMeier estimate of the survivor function. (b) Create a plot that compares the KaplanMeier estimates of the survivor functions for the two sexes separately. Describe what you see in this plot. (c) Use the coxph function to estimate the hazard proportion between the two sexes. Explain to someone who is not familiar with the model how you would interpret the meaning of this number. For instance, what does it say about the different probabilities of going a month without an infection? ((1) Give a 95% condence interval for the hazard ratio. Does this result match with your graph from part (b)? (e) Looking at the KaplaniMeier estimate for the male group, the observation in row 42 is concerning to me. Why am I concerned? Explore how your analysis would change if that one observation was removed