Zita€™s Restaurant is a chain that employs independent evaluates to visit its restaurants as customers and assess the quality of the service by filling out a question-naire. The company evaluates restaurants in two categories: products (the food) and service (e.g., promptness, order accuracy, courtesy, friendliness). The evaluate considers not only his or her order experiences, but also observations throughout the restaurant. Following are the results of an evaluation's 20 visits to one particular restaurant during a month showing the number of €œdefects€ noted in the service category:

Construct a control chart for this restaurant using 3σ limits to monitor quality service and indicate if the process is in control.

Transcribed Image Text:

Sample Number of Defects 4 10 3 8. 10 11 12 13 14 15 13 16 9. 17 10 18 11 19 15 20 12 %3D