A local delivery service has 40 drivers who deliver packages throughout the metropolitan area. Occasionally, drivers make mistakes, such as entering the wrong package number, failing to get a signature, and so on. A total of 240 mistakes were made in one year as shown in Table 3.5. The manager in charge of this operation has issued a disciplinary citation to drivers for each mistake.

1. 1. What is your opinion of the manager's approach? How does it compare with the Deming philosophy?
2. 2. How might the analysis of these data help the manager to understand the variation in the system? Do you think all of the variation stems from common causes? If not, why not? How can the data help the manager to improve the performance of the system or be used to reward good performance?