Jay, a rural fire service volunteer, decided to apply control chart methodology, learned in a business statistics class, to data collected by the local brigade. Jay wants to determine whether weeks containing more than the mean number of incidents attended were due to inherent, chance causes of variation, or if there were special causes of variation such as increased arson, severe drought or holiday-related activities, or other emergencies including searches, storms and floods.

The file < INCIDENTS > contains the number of incidents attended per week (Sunday to Saturday) over the past year.

a. What is the mean number of incidents attended per week?

b. Construct a c chart for the number of incidents attended per week.

c. Is the process in a state of statistical control?

d. Weeks 15 and 41 experienced seven incidents each. Are these large values explainable by common causes, or does it appear that special-cause variation occurred in these weeks?

e. Explain how the local fire brigade can use these data to chart and monitor future weeks in real-time (i.e. on a weekto-week basis)?