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OM5 C16 IM
© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly
accessible website, in whole or in part.
17
14.* Use the data in problem 4 to calculate Cp , Cpl , Cpu, and Cpk , assuming that the
specifications are 3.75 ± 1.30. Interpret the results for the manager of this process.
Using the Process Capability Excel template, we obtain the following:
OM5 C16 IM
© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly
accessible website, in whole or in part.
18
15.* The worksheet C16P15 in the OM5 Data Workbook provides sample times in hours
for processing and shipping orders from a Web-based retailer. The retailer advertises
that orders are shipped within 4 hours of receipt. What is the capability of the process
to achieve this standard? Explain your conclusions.
OM5 C16 IM
© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly
accessible website, in whole or in part.
19
Note that although no values are outside of the specification limits, the capability
indexes are less than one. The instructor might ask the students why this is so. This
Case Teaching Note: The Casey Company
The Casey Co. is a distributor of electrical automation and power transmission products.
When the company began to implement a total quality management process, one manager
was eager to collect data about the organization’s receiving process because of a decrease
in the organization’s on-time deliveries. The manager suspected that the data entry person
in the purchasing department was not entering data in the computer in a timely fashion;
consequently, packages could not be properly processed for subsequent shipping to the
customer.
A preliminary analysis indicated that the manager’s notion was inaccurate. In fact, the
manager was able to see that the data entry person was doing an excellent job. The
analysis showed that handling packages that were destined for a branch operation in the
same fashion as other packages created significant delays. A simple process change of
placing a branch designation letter in front of the purchase order number told the
receiving clerk to place those packages on a separate skid for delivery to the branch.
However, this analysis revealed a variety of other problems. These were found to
contain many errors in addition to the wrong destination designation that contributed to
OM5 C16 IM
© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly
accessible website, in whole or in part.
20
the delays. Errors included
A Wrong quantity
Many packing slips contained multiple errors. The data in the worksheet C16 Case in the
OM5 Data Workbook shows the number of packing slips and total errors identified for 50
samples of 275 of packing slips.
Case Questions for Discussion
1. Construct and interpret a control chart for the packing slip data.
The c-chart calculations are summarized on the portion of the c-Chart Excel
OM5 C16 IM
© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly
accessible website, in whole or in part.
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2. Conduct a Pareto analysis of the errors.
Calculating the percentages for each category, we find that category A
accounts for 37% of errors; category B, 27%; category C, 17%; category D
3. What information might a separate chart for each error category provide? Conduct
a more thorough analysis for each error category, and draw conclusions and
recommendations for improving the process.
A chart for each category can provide insight into whether the number of each type
of error is in control or not. As seen in the charts below, Categories A, B, and C
Error Category A
OM5 C16 IM
© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly
accessible website, in whole or in part.
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Error Category B
Error Category C
Error Category D
OM5 C16 IM
© 2013 Cengage Learning. All Rights Reserved. May not be scanned, copied or duplicated, or posted to a publicly
accessible website, in whole or in part.
23
Error Category E
