Operations and Supply Chain Management 9th edition
9th Edition
ISBN: 9781119320975
Author: Roberta S. Russell, Bernard W. Taylor III
Publisher: WILEY
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Chapter 3, Problem 6P
Summary Introduction
To construct: A c-chart and determine whether the process is in control or not?
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Southern Mills Company
One of the stages in the process of making denim cloth at the Southern Mills Company is to spin
cotton yarn onto spindles for subsequent use in the weaving process. Occasionally the yarn breaks
during the spinning process, and an operator ties it back together. Some number of breaks is
considered normal; however, too many breaks may mean that the yarn is of poor quality. In order to
monitor this process, the quality-control manager randomly selects a spinning machine each hour
and checks the number of breaks during a 15-minute period. Following is a summary of the
observations for the past 20 hours.
Construct a c-chart using 3 limits for this process and indicate if the process was out of control at
any time.
Number of
Number of
Sample
Breaks
Sample
Breaks
1
3
11
2
12
4
3
4
13
6
1
14
7
5
5
15
8
6
3
16
6
7
2
17
5
8
4
18
7
19
8
10
2
20
6
One of the stages in the process of making denim cloth at the Southern Mills Company is to spin cotton yarn onto spindles for subsequent use in the weaving process. Occasionally the yarn breaks during the spinning process, and an operator ties it back together. Some number of breaks is considered normal; however, too many breaks may mean that the yarn is of poor quality. In order to monitor this process, the quality-control manager randomly selects a spinning machine each hour and checks the number of breaks during a 15-minute period. Following is a summary of the observations for the past 20 hours.
Construct a c-chart using 3 limits for this process and indicate if the process was out of control at any time.
West Battery Corp. has recently been receiving complaints from retailers that its 9-volt batteries are not lasting as long as other name brands. James West, head of the TQM program at
West's Austin plant, believes there is no problem because his batteries have had an average life of 60 hours, about 10% longer than competitors' models. To raise the lifetime above this
level would require a new level of technology not available to West. Nevertheless, he is concerned enough to set up hourly assembly line checks. Previously, after ensuring that the
process was running properly, West took samples of 5 9-volt batteries for 25 test to establish the standards for control chart limits. Those 25 tests are shown in the following table:
Sample Data
Sample Data
Hour
Hour
Sample
Taken
1
Sample
Taken
1
2
4
5
R
2
3
4
R
1
60
61
60
59
67
61.4
8
14
62
69
51
62
56
60.0
18
55
57
70
56
46
56.8
24
15
67
53
63
69
70
64.4
17
60
45
58
49
57
53.8
15
16
72
58
51
44
64
57.8
28
66
81
61
51
60
63.8
30
17
49
49
58
68…
Chapter 3 Solutions
Operations and Supply Chain Management 9th edition
Ch. 3.S - Prob. 1QCh. 3.S - Prob. 2QCh. 3.S - Prob. 3QCh. 3.S - Prob. 4QCh. 3.S - Prob. 5QCh. 3.S - Prob. 6QCh. 3.S - Prob. 7QCh. 3.S - The Great Lakes Company, a grocery store chain,...Ch. 3.S - Prob. 2PCh. 3.S - Prob. 3P
Ch. 3.S - The Fast Break Computer Company assembles personal...Ch. 3.S - Prob. 5PCh. 3 - Using Sampling and Statistics to Analyze...Ch. 3 - Prob. 2.1ASCCh. 3 - Prob. 3.1ASCCh. 3 - Prob. 4.1ASCCh. 3 - Prob. 5.1ASCCh. 3 - Prob. 1QCh. 3 - Prob. 2QCh. 3 - Prob. 3QCh. 3 - Prob. 4QCh. 3 - Prob. 5QCh. 3 - Prob. 6QCh. 3 - Prob. 7QCh. 3 - Prob. 8QCh. 3 - Prob. 9QCh. 3 - Prob. 10QCh. 3 - Prob. 11QCh. 3 - Prob. 1PCh. 3 - Prob. 2PCh. 3 - Prob. 3PCh. 3 - Prob. 4PCh. 3 - Prob. 5PCh. 3 - Prob. 6PCh. 3 - Prob. 7PCh. 3 - Prob. 8PCh. 3 - Prob. 9PCh. 3 - Prob. 10PCh. 3 - Prob. 11PCh. 3 - Prob. 12PCh. 3 - Prob. 13PCh. 3 - Prob. 14PCh. 3 - Prob. 15PCh. 3 - Prob. 16PCh. 3 - Prob. 17PCh. 3 - Prob. 18PCh. 3 - Prob. 20PCh. 3 - Prob. 21PCh. 3 - Prob. 22PCh. 3 - Prob. 23PCh. 3 - Prob. 24PCh. 3 - Prob. 25PCh. 3 - Prob. 26PCh. 3 - Prob. 27PCh. 3 - Prob. 28PCh. 3 - Prob. 29PCh. 3 - Prob. 30PCh. 3 - Prob. 32PCh. 3 - Prob. 33PCh. 3 - Prob. 34PCh. 3 - Prob. 36PCh. 3 - Prob. 37PCh. 3 - Prob. 38PCh. 3 - Prob. 39PCh. 3 - Prob. 40PCh. 3 - Elon Corporation manufactures parts for an...Ch. 3 - Prob. 42PCh. 3 - Prob. 44PCh. 3 - Prob. 45PCh. 3 - Prob. 46PCh. 3 - Prob. 47PCh. 3 - Metropolitan General Hospital is a city-owned...Ch. 3 - Prob. 50PCh. 3 - Prob. 51PCh. 3 - The Shuler Motor Mile is a high-volume discount...Ch. 3 - Prob. 1.1CPCh. 3 - Prob. 2.1CPCh. 3 - Improving Service Time at Daves Burgers Daves...
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