Consider given Exercise. under the assumption that the complication rate is 0.1%. If you were to construct a p-chart using two-sided 3σ limits, what would the minimum sample size be to detect an improvement in the process?
Exercise
The number of heart surgery complications is rare. To monitor the effectiveness of such surgeries, data are recorded on the number of such procedures until a complication occurs. These complications occur independently with a constant probability of occurrence and follow a geometric distribution. Table shows such data for a sequence of 25 complications. It is estimated from past data that the complication rate is 0.1%.
Construct an appropriate control chart and comment on the process assuming a type I error rate of 0.005. What would the control limits be for a type I error rate of 0.05? What factors would influence your selection of the type I error rate?
|
Complication Sequence
|
Number of Procedures
|
Complication Sequence
|
Number of Procedures
|
Complication Sequence
|
Number of Procedures
|
|
1
|
654
|
10
|
1654
|
18
|
1794
|
|
2
|
981
|
11
|
892
|
19
|
1112
|
|
3
|
1508
|
12
|
750
|
20
|
652
|
|
4
|
436
|
13
|
1333
|
21
|
1050
|
|
5
|
1202
|
14
|
1404
|
22
|
1085
|
|
6
|
889
|
15
|
909
|
23
|
1422
|
|
7
|
1854
|
16
|
822
|
24
|
688
|
|
8
|
3068
|
17
|
1609
|
25
|
1095
|
|
9
|
704
|
|
|
|
|