The Cattleman's Bar and Grille Would Like to Use Statistical

Short Answer

The Cattleman's Bar and Grille would like to use statistical process control to monitor the time that elapses between a customer's arrival and when the food is served.The manager has determined that the average time between customer arrival and service is 19.5 minutes with a standard deviation of 2.5 minutes.Each evening,the manager plans on selecting 4 tables at random and will measure the elapsed time.What would the 3-sigma control limits be for the X-bar chart?