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

Must show:

$a.$ The $UC\frac{L}{L}CLlimits$ for both charts result from your analysis.

$UC{L}_x=+?(?)=,LC{L}_x=+?(?)=$

$UC{L}_R=*?=,LC{L}_R=*?=$

$b.$ Plot the control charts and label the UCL, central line, and $LCLon$ both charts.

Failure $todoso$ receives $no$ credit.

$c.$ Explain whether the process $isin$ control $or$ not. Did they manage $to$ meet the expected service

time goal $of2\mathrm{.}0$ minutes?

$In$ a situation where the process $is$ not under control, which $TQM$ tool would you suggest $to$ identify

the cause $of$ the issue and improve customer service? Provide your rationale for your chosen tool. Observations $of$ Service Time $($ min $)$ 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 $toat$ least $2\mathrm{.}0$ minutes and

ideally $1\mathrm{.}5$ minutes $tobe$ competitive.

These quality improvements were implemented over several months, and their effect was immediate.

Service speed was improved, and market share increased $by5\%at$ 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: