3. Continue with the previous problem, and recall: Group I is a high vitamin C diet group, and group II is a high calcuium diet group. The data, and the ranked observations follow: GroupI -10.41 -1.23 0.51 0.79 1.06 1.22 1.98 2.32 2.75 4.41 Rank 1 4 10 11 13 14 16 17' 18 19 Group II -3.15 -1.68 -0.62 -0.38 -0.25 -0.21 -0.18 0.92 1.56 Rank 2 3 5 6 7 8 9 12 15 (a) (3 points) Assume the 90% condence interval for the shift parameter for group I vs. group I I is : ( -2.90, -0.42 ). Interpret this interval in terms of the problem. (b) (3 points) Write down one possible permutation for the ranks of the observations from group I, and calculate the corresponding Wilcoxon Rank Sum test-statistic. (c) (3 points) What assumptions had to be made in order for the non-parametric condence interval in (a) to be valid? ((1) (3 points) What aspect / s of the data may suggest that a parametric technique is not appropriate