Answer Happy

The management of the Diners Delight franchised restaurant chainis in the process of establishing quality-control charts for thetime that its service people give to each customer. Managementthinks the length of time that each customer is given should remainwithin certain limits to enhance service quality. A sample of sixservice people was selected, and the customer service they providedwas observed four times. The activities that the service peoplewere performing were identified, and the time to service onecustomer was recorded as noted below:
Service
Person
Service Time (sec)
Sample 1
Sample 2
Sample 3
Sample 4
1
200
150
175
114
2
120
85
105
75
3
83
93
130
150
4
68
86
145
175
5
110
90
75
105
6
89
65
115
125
Determine the upper control limits for an X-chart.