A Stat 510 student works at the IT Help Desk at Hale Library. For several weeks, the student recorded how long it took to solve the walk-in problems she attended. A random sample of n = 14 walk-in problems was selected and times are listed below. 18.60 19.30 18.48 12.88 17.02 14.62 17.36 17.50 22.18 22.17 17.51 18.92 19.52 20.31 8. Using the data, calculate the 90% C.I. for #, the mean time it takes for the student to solve a walk-in problem. Think about the assumptions you made. Hint: R commands mean(o) and sd(a) could be useful. (a) [13.8167, 22.8076] (b) [17.1172, 19.5071] (c) [17.1962, 19.4281] (d) [17.1106, 19.5136] (e) [17.3961, 19.2281] (f) None of the others