Dicks' Burgers restaurant in Seattle has followed the lead of large franchise restaurants like Burger King, McDonald's, and Wendy has and constructed drive-through windows in one of its locations. However, instead of making Dicks' more competitive, the drive-through window has been a source of continual problems, and it has lost market share to its competitors in that location. To identify and correct the problems, top management has implemented a quality management program at this location. A quality team made up of employees, managers, , and quality specialists from headquarters, using traditional quality tools like Pareto charts, check sheets, fishbone diagrams, and process flowcharts, have determined that the primary problem is slow, erratic service at the drive-through window. Studies show that the time a customer arrives at the window to the time the order is received averages 2.6 minutes. To be competitive, management believes service time should be reduced to at least 2.0 minutes and ideally 1.5 minutes.

These quality improvements were implemented over several months, and their effect was immediate. Service speed was improved, and market share increased by 5% at this location. To maintain quality service, make sure the service time remained fast, and continue to improve service, the quality team decided to use statistical process control charts on a continuing basis. They collected six service time observations daily over 15 days as follows:

DISCUSSION QUESTIONS

1.Construct x-bar and R control charts to monitor the service at the drive-through window.

Plot the control charts and explain whether the process is in control or not.

2.What actions should the quality team to take if the process is out of control?

Observations of Service Time (min) Sample 1 2 3 4 5 6 1.62 1.54 1.38 1.75 2.5 1.32 1.25 1.96 1.55 W N H 1.66 1.38 2.01 1.85 1.01 0.95 1.79 1.66 1.94 3.1 1.18 1.25 1.45 1.09 2.11 1.95 0.76 1.34 2.12 1.45 1.03 VOU A 0.88 2.50 1.07 1.50 1.33 1.62 1.55 1.41 1.95 1.14 1.86 1.02 8 2.78 1.56 1.87 2.03 0.79 1.14 1.31 1.05 0.94 1.53 1.71 1.15 10 1.67 1.85 2.03 1.12 1.5 1.36 11 0.95 1.73 1.12 1.67 2.05 1.42 12 3.21 4.16 1.67 1.75 2.87 3.76 13 1.65 1.78 2.63 1.05 1.21 2.09 14 2.36 3.55 1.92 1.45 3.64 2.3 15 1.07 0.96 1.13 2.05 0.91 1.66