The operations manager of an airline check-in counter is interested in evaluating the service provided to the company's customers. In particular, she would like to make sure that customers are not waiting an excessively long time prior to being served at the check-in facility. Ideally, she would like to see that customers wait, on average, less than 7 minutes prior to being served at the check-in counter. The file P20_08.xlsx contains the waiting times (in minutes) of 5 randomly selected passengers, observed during the same hour on each of 25 different days.

a. Construct and interpret X and R charts for the given data. Based on these charts, does this service process appear to be in control?

b. Are there any other indications that the given service process may be out of control? If so, explain.

c. What specific advice would you give to the operations manager for improving customer service, at least in the short run?