In the article Accelerating Improvement published in Quality Progress, Gaudard, Coates, and Freeman describe a restaurant that caters to business travelers and has a self-service

In the article €œAccelerating Improvement€ published in Quality Progress, Gaudard, Coates, and Freeman describe a restaurant that caters to business travelers and has a self-service breakfast buffet. Interested in customer satisfaction, the manager conducts a survey over a three-week period and finds that the main customer complaint is having to wait too long to be seated. On each day from September 11 to October 1, a problem-solving team records the percentage of patrons who must wait more than one minute to be seated. A time series plot of the daily percentages is shown in Figure 1.10. What does the time series plot tell us about how to improve the waiting time situation?

Figure 1.10

9% 8% 7% 6% 5% 3% 2% 1% MTWTFSSMTWT FSS MTWT FSS Day of week (Sept. 11- Oct. 1) Percentage who waited