Refer to given Exercise and the data shown in Table. Construct a control chart for the number of dissatisfied customers. Revise the chart, assuming special causes for points outside the control limits.
Exercise
The number of customers who are not satisfied with the service provided in a retail store is found for 20 samples of size 100 and is shown in Table. Construct a control chart for the proportion of dissatisfied customers. Revise the control limits, assuming special causes for points outside the control limits.
|
Sample
|
Number of dissatisfied customers
|
Sample
|
Number of dissatisfied customers
|
|
1
|
2
|
11
|
5
|
|
2
|
5
|
12
|
4
|
|
3
|
4
|
13
|
2
|
|
4
|
3
|
14
|
5
|
|
5
|
4
|
15
|
3
|
|
6
|
2
|
16
|
12
|
|
7
|
3
|
17
|
3
|
|
8
|
2
|
18
|
2
|
|
9
|
4
|
19
|
5
|
|
10
|
11
|
20
|
2
|