Question: In many manufacturing processes, the term work-in-progress (often abbreviated WIPP) is used. In a book manufacturing plant, the WIP represent the time it takes for sheets from a press to be folded, gathered, sewn, tipped on end sheets, and bound. The data contained in the file wip.xls represent samples of 20 books at each of tow production plants and the processing time (operationally defined as the time, in days, from when the books came off the press to when they were packed in cartons) for these jobs:

5.62 5.29 16.25 10.92 11.46 21.62 8.45 8.58 5.41 11.42

11.62 7.29 7.50 7.96 4.42 10.50 7.58 9.29 7.54 8.92

9.54 11.46 16.62 12.62 25.75 15.41 14.29 13.13 13.71 10.04

5.75 12.46 9.17 13.21 6.00 2.33 14.25 5.37 6.25 9.71

For each of the two plants:

a. Compute the mean, median, first quartile, and third quartile.

b. Compute the range, interquartile range, variance, standard deviation, and coefficient of variation.

c. Construct side-by-side box-and-whisper plots. Are the data skewed? If so, how?

d. On the basis of the results of (a) through (c), are there any differences between the two plants? Explain.