Operations Management Homework #5 – Process Control Charts
Operations Management
Homework
Problem 1:
You are the newly appointed assistant administrator at a local hospital and your first project is to investigate the quality of the patient meals put out by the food-service department. You conducted a 10-day survey by submitting a simple questionnaire to the 400 patients with each meal, asking that they simply check off that the meal was either satisfactory or unsatisfactory. For simplicity in this problem, assume that the response was 1,000 returned questionnaire from the 1,200 meals each day. The results are as follows:
NUMBER OF UNSATISFACTORY MEALS
SAMPLE SIZE
December 1
74
1,000
December 2
42
1,000
December 3
64
1,000
December 4
80
1,000
December 5
40
1,000
December 6
50
1,000
December 7
65
1,000
December 8
70
1,000
December 9
40
1,000
December 10
75
1,000
600
10,000
Construct a p chart based on the questionnaire results, using two standard deviations.
What comments can you make about the results of the survey?
Problem 2:
Resistors for electronic circuits are manufactured on a high-speed automated machine. The machine is set up to produce a large run of resistors of 1,000 ohms each.
To set up the machine and to create a control chart to be used throughout the run, 15 samples were taken with four resistors in each sample. The sample information with mean and range is listed as follows:
Sample
1
2
3
4
mean
range
1
1010
991
985
986
993.00
25
2
995
996
1009
994
998.50
15
3
990
1003
1015
1008
1004.00
25
4
1015
1020
1009
998
1010.50
22
5
1013
1019
1005
993
1007.50
26
6
994
1001
994
1005
998.50
11
7
989
992
982
1020
995.75
38
8
1001
986
996
996
994.75
15
9
1006
989
1005
1007
1001.75
18
10
992
1007
1006
979
996.00
28
11
996
1006
997
989
997.00
17
12
1019
996
991
1011
1004.25
28
13
981
991
989
1003
991.00
22
14
999
993
988
984
991.00
15
15
1013
1002
1005
992
1003.00
21
Develop an chart and an R chart and plot the values. From the charts, what comments can you make about the process