1. A hospital is analyzing nosocomial infections and wants to reduce their infection rate below the
national average of 2.0%. They have sampled 40 cases every week for the last 20 weeks. The
data are shown below. Create p and np control charts. Interpret the graphs. How is the hospital
performing in relation to its stated goal?
SAMPLE
1
2
3
4
5
6
7
8
9
10
INFECTIONS
2
1
1
2
1
1
3
2
1
2
SAMPLE
11
12
13
14
15
16
17
18
19
20
INFECTIONS
3
4
2
3
4
5
3
4
5
6
2. Walter Shewhart presented the following data in his classic Economic Control of Quality of
Manufactured Product. Create a p chart for each machine. Does either of the two machines
show evidence of special cause variation?
Month
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sept
Oct
Nov
Dec
Average
Machine A
Defective
4
5
5
2
15
3
3
2
3
13
5
3
5.25
Machine A
Inspected
527
610
428
400
498
500
395
393
625
465
446
510
483.08
Machine B
Defective
1
3
1
1
1
1
1
2
1
1
3
1
1.42
Machine B
Inspected
169
99
208
196
132
89
167
200
171
122
107
132
149.33
3. From January 1846 through December 1848 Semmelweis ([1860] 1983) recorded births and
the number that resulted in the death of the mother at his hospital. The data available in the
Ch07.xsl file , in the Problem07-03 tab. Create a p chart to analyze performance. Interpret
the chart. Was the system stable?
4. Post Surgical infections have been reported to affect 2% to 5% of the 16 million patients who
undergo surgery in US hospitals. Infections increase the chance of compilations and death.
Antibiotics given one hour prior to surgery have been shown to reduce the probability of
infection. The director of quality improvement has sampled 20 patients per week over the
preceding 25 weeks. The data is presented below. The data collected records whetehr a
patient contracted an infection after surgery. Assuming that the average rate of infection is
3.5%, create a control chart to analyze performance.
Sample
Patient
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
2
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
3
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
4
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
5
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
6
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
7
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
8
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
9
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
10
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
11
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
12
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
13
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
14
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
15
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
16
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
17
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
18
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
19
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
20
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
5. Readmission rates within one year for congestive heart failure have been documented at
35%. A local heart program wants to assess its performance against this standard. The
program has randomly selected ten patients per month over a 24-month period for review.
The data is available below. Some of the patients were deleted from the sample due to
death, relocation, or other reasons that preclude follow-up. Create an appropriate SPC chart
to analyze performance.
Month
Readmits
Sample
Jan
3
10
Feb
3
10
Mar
4
10
Apr
3
8
May
3
10
Jun
3
9
Jul
3
10
Aug
3
9
Sep
3
9
Oct
3
10
Nov
3
9
Dec
2
10
Jan
3
10
Feb
2
8
Mar
3
10
Apr
2
9
May
3
10
Jun
2
9
Jul
3
10
Aug
3
10
Sep
2
10
Oct
2
10
Nov
2
8
Dec
2
9
