The following data represent the length of time, in days, to recovery for patients randomly treated with one of two medications to clear 11p severe bladder infections: Medication 1: 111 = 14, 31 = 1?, sf = 1.5. Medication 2: 11.2 = 16, f2 = 19, $5} = 1.8. Assume that the recovery times are normally distributed. (a) Construct a 95% condence interval for the ratio of two population variances. (b) Find a 95% pooled two-sample r condence interval for the difference in the mean recovery times for the two medications. Is this method valid? (c) Do data provide sufcient evidence to show (i) the two population variances differ. and (ii) the mean recovery times for the two medications differ