Archie is fed up with waiting in line at his local post office and decides to take action. Over the course of the next few months, he records the waiting times for each of a random selection of 25 post office visits made by him and other customers. These waiting times (in minutes) are are as follows: 25, 18, 19, 29, 31, 9, 28, 17, 25, 11, 21, 15, 8, 16, 30, 24, 12, 23, 20

Required:
Construct a box-and-whisker plot for the data.