55. Here is a stem-and-leaf display of the escape time data introduced in Exercise 36 of this chapter.

32 55 33 49 34 35 6699 36 34469 37 03345 38 9 39 2347 40 23 41 42 4

a. Determine the value of the fourth spread.

b. Are there any outliers in the sample? Any extreme outliers?

c. Construct a boxplot and comment on its features.

d. By how much could the largest observation, currently 424, be decreased without affecting the value of the fourth spread?