The University Health Network (UHN) has grown out of a series of mergers between Toronto hospitals, and has adjusted and change to accommodate the growing and changing patient community in and around the Greater Toronto Area (GTA).

UHN monitors and evaluates healthcare providers according to strict standards and guidelines. Improvement in the quality of care is a principal concern. Hospitals are required to identify and monitor important quality indicators that affect patient care and establish "thresholds for evaluation" (TFEs), which are levels at which special investigation of problems should occur. TFEs provide a means of focusing attention on non-random errors (that is, special cause of variation). A logical way to set TFEs is through control charts.

Suppose that UHN collects monthly data on the number of infections after surgery. This data is provided in the attached spreadsheet. Hospital administrators are concerned about whether the high percentages of infections (such as 1.76% in month 12) are caused by factors other than randomness.

1) Using the data provided what is the average percentage of infections?

2) Do the following:

a. Construct the most appropriate control chart to use for this data,

b. Compute the upper and lower control limits,

c. Plot the data on a control chart, and

d. Determine if the process is in statistical control.

3) Based on your analysis, what action, if any, should management take?

Data in Excel sheet:

Month	Surgeries	Infections
1	208	1
2	225	3
3	201	3
4	236	1
5	220	3
6	244	1
7	247	1
8	245	1
9	250	1
10	227	0
11	234	2
12	227	4
13	213	2
14	212	1
15	193	2
16	182	0
17	240	1
18	230	1
19	187	1
20	252	2
21	201	1
22	226	0
23	222	2
24	212	2
25	219	1
26	223	2
27	191	1
28	222	0
29	231	3
30	239	1
31	217	2
32	241	1
33	220	3
34	278	1
35	255	3
36	225	1