Refer to the information provided in E9-19. Control charts are designed to signal when an out-of-control event has occurred. However, the chart does not indicate the reason for the out-of-control event. Individuals must serve as detectives to investigate possible reasons for special cause variation.

a. Identify the types of questions you would ask in attempting to understand the cause of the lower percentages in periods 9 and 10. (For example, was there turnover in payroll staff during these periods?)

b. Though control charting techniques originally were developed to monitor manufacturing processes, their use has expanded beyond the manufacturing floor. Identify other examples of how control charts could be used to monitor the quality of administrative (or service-related) processes.