Statistics for Business and Economics (13th Edition)
13th Edition
ISBN: 9780134648385
Author: MCCLAVE
Publisher: PEARSON
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Textbook Question
Chapter 13.6, Problem 13.46ACB
Rental car call center study. A worldwide rental car company receives about 10,000 customer complaint calls per month at its European call center. In an effort to reduce the proportion of issues that are not resolved on the customer’s first call, management conducted a thorough study of the call center’s procedures. The results were published in the International Journal of Productivity and Performance Management (Vol. 59, 2010). After making major changes at the call center, management constructed a p-chart to monitor the process improvements. Assume that 18 calls to the center were sampled each day for 60 consecutive days. The article reported that the proportion of all calls in the sample that had unresolved issues at the end of the call was .107. (This was a major improvement over the previous unresolved-first-call rate of .845.)
a. What is the centerline for the p-chart?
b. Compute the lower and upper control limits for the p chart.
c. When the proportions of daily calls that resulted in unresolved issues are plotted on the p-chart. all fall within the LCL and UCL boundaries. What does this imply about the process?
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Chapter 13 Solutions
Statistics for Business and Economics (13th Edition)
Ch. 13.4 - What is a control chart? Describe its use.Ch. 13.4 - Explain why rational subgrouping should be used in...Ch. 13.4 - When a control chart is first constructed, why are...Ch. 13.4 - Which process parameter is an x -chart used to...Ch. 13.4 - Even if all the points on an x -chart fall between...Ch. 13.4 - What must be true about the variation of a process...Ch. 13.4 - Use the six pattern-analysis rules described in...Ch. 13.4 - Consider the x -chart shown below. a. Is the...Ch. 13.4 - Use Table IX on page 13-74 to find the value of A2...Ch. 13.4 - Twenty-five consecutive samples of size n = 5 were...
Ch. 13.4 - The data in the following table were collected for...Ch. 13.4 - Prob. 13.12ACBCh. 13.4 - Active pharmaceutical ingredient. During the...Ch. 13.4 - Detecting gender-related employment disparities....Ch. 13.4 - Pain levels of ICU patients. Various interventions...Ch. 13.4 - Quality control for irrigation data. Most farmers...Ch. 13.4 - Improving public health waiting times. Statistical...Ch. 13.4 - Cereal box manufacturing. A machine at K-Company...Ch. 13.4 - Detecting under-reported emissions. The...Ch. 13.4 - 13 20 Selecting the best wafer-slicing machine....Ch. 13.4 - Chunky data. BPI Consulting, a leading provider of...Ch. 13.4 - Military aircraft bolts. A precision parts...Ch. 13.5 - What characteristic of a process is an R-chart...Ch. 13.5 - Prob. 13.24LMCh. 13.5 - Use Table IX on page 13-74 to find the values of...Ch. 13.5 - Construct and interpret an R-chart for the data in...Ch. 13.5 - Construct and interpret an R-chart for the data in...Ch. 13.5 - Construct and interpret an R-chart and an x -chart...Ch. 13.5 - Weight of packed frozen scallops. In Quality...Ch. 13.5 - Detecting gender-related employment disparities....Ch. 13.5 - Pain levels of ICU patients. Refer to the Research...Ch. 13.5 - Quality control for irrigation data. Refer to...Ch. 13.5 - Lowering the thickness of an expensive blow-molded...Ch. 13.5 - Cola bottle filling process. A soft-drink bottling...Ch. 13.5 - Chunky data. Refer to Exercise 13.21e (p. 13-40)...Ch. 13.5 - Replacement times for lost ATM cards. In an effort...Ch. 13.5 - Military aircraft bolts. Refer to the...Ch. 13.5 - Precision of scale weight measurements. The...Ch. 13.6 - What characteristic of a process is a p-chart...Ch. 13.6 - In each of the following cases, use the sample...Ch. 13.6 - The proportion of defective items generated by a...Ch. 13.6 - To construct a p-chart for a manufacturing...Ch. 13.6 - To construct a p-chart, 20 samples of size 150...Ch. 13.6 - Academic failure rates in Nigeria. The quality...Ch. 13.6 - Monitoring surgery complications. An article on...Ch. 13.6 - Rental car call center study. A worldwide rental...Ch. 13.6 - Defective micron chips. A manufacturer produces...Ch. 13.6 - Hand break cable defects. In Control Engineering...Ch. 13.6 - Monitoring newspaper typesetters. Accurate...Ch. 13.6 - Quality of rewritable CDs. A Japanese compact disc...Ch. 13.6 - Leaky process pumps. Quality (February 2008)...Ch. 13.6 - Rubber company lire tests. Goodstone Tire Rubber...Ch. 13.7 - Explain why it is inappropriate to conduct a...Ch. 13.7 - Explain the difference between process spread and...Ch. 13.7 - Describe two different ways to assess the...Ch. 13.7 - Why is it recommended to use and interpret Cp in...Ch. 13.7 - For a process that is in control and follows a...Ch. 13.7 - Find the specification spread for each of the...Ch. 13.7 - Find (or estimate) the process spread for each of...Ch. 13.7 - Find the value of Cp for each of the following...Ch. 13.7 - Upper specification limit of a process. An...Ch. 13.7 - Capability of an in-control process. A process is...Ch. 13.7 - Water use at a thermal power plant. Thermal power...Ch. 13.7 - Cereal box filling process. Refer to the data on...Ch. 13.7 - Military aircraft bolts. Refer to Exercise 13.22...Ch. 13.7 - Bioreactor production of antibodies. Benchtop...Ch. 13.7 - Driver gear bore holes. During the manufacture of...Ch. 13.7 - Lowering the thickness of an expensive blow-molded...Ch. 13 - Define quality and list its important dimensions.Ch. 13 - What is a process? Give an example of an...Ch. 13 - What is a system? Give an example of a system with...Ch. 13 - Describe the six major sources of process...Ch. 13 - Suppose all the output of a process over the last...Ch. 13 - Processes that are in control are predictable;...Ch. 13 - Compare and contrast special and common causes...Ch. 13 - Explain the difference between control limits and...Ch. 13 - Should control charts be used to monitor a process...Ch. 13 - Under what circumstances is it appropriate to use...Ch. 13 - A process is under control and follows a normal...Ch. 13 - Weight of a product. Consider the time series data...Ch. 13 - Lengths of pencils. The length measurements of 20...Ch. 13 - Applying pattern-analysis rules. Use the...Ch. 13 - Defective plastic mold. A company that...Ch. 13 - Robotics clamp gap width. Control chart...Ch. 13 - Package sorting time. AirExpress. an overnight...Ch. 13 - Waiting times of airline passengers. Officials at...Ch. 13 - Defects in graphite shafts. Over the last year, a...Ch. 13 - New iron-making process. Mining Engineering...Ch. 13 - CPU of a computer chip. The central processing...Ch. 13 - Bayfield Mud Company case. The text Quantitative...
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