Case $3--$ Improving Service Time at $($Dickis Burgers

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. Did they manage to meet the expected service time goal of $2\mathrm{.}0$ minutes?

Show the control limits below with the numbers you obtain as the result of your analysis.

UCL, $=$ x $+$ x $($x$)=$ x LCLx$=$ x $+$x $($x$)=$x

UCLa $=$ x $+($x$)=$ x

LCLR$=$ x $+($x$)=$ x

Failure to do so receives no credit.

$2.$ What is the most appropriate TQM tool you recommend for identifying the cause of the problem and improving customer service? Explain why you chose this tool.

The Dicks' Burgers restaurant in Seattle has followed the lead of large franchise restaurants such as

Burger King, McDonald's and Wendy's by building 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. The top

management has implemented a quality management program to identify and correct potential

problems. A quality team of employees, managers and quality specialists from the headquarters, using

traditional quality tools such as Pareto charts, check sheets, fishbone diagrams and process flow

diagrams, have determined that the primary problem is slow and erratic service at the drive$-$through

window. Studies show that the time a customer arrives at the window to when the order is received

averages $2\mathrm{.}6$ minutes. Management believes service time should be reduced to at least $2\mathrm{.}0$ minutes and

ideally $1\mathrm{.}5$ minutes to be competitive.

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, ensure the service time remained fast, and continue to improve service, the quality team

continued using statistical process control charts. They collected Eight service time observations daily

over $15$ days as follows: