Refer to given Exercise. Construct an OC curve for the p-chart. If the process proportion of dissatisfied customers were to rise to 7%, what is the probability of not detecting this shift on the first sample drawn after the change has taken place? What is the probability of detecting the shift by the third sample?
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
|