Test-Bank-for-Heizer-Operations-Management-9e

131.Larry's boat shop wants to monitor the number of blemishes in the paint of each boat. Construct a c-chart to determine if their paint process is in control using the following data.

Sample Number	Number of
	Defects
1	3
2	4
3	2
4	1
5	3
6	2
7	1
8	4
9	2
10	3
Total units sampled	10
Total defects	25
Defect rate, c-bar	2.5
Standard deviation	1.581
z value	3
Upper Control Limit	7.243
Center Line	2.5
Lower Control Limit	0

	8
UCL
Mean	6
	4
	2
	0
	1	2	3	4	5	6	7	8	9	10
					Sample

The process is in control. (Statistical Process Control (SPC), moderate) {AACSB: Analytic Skills}

132.The specifications for a manifold gasket that installs between two engine parts calls for a thickness of 2.500 mm + .020 mm. The standard deviation of the process is estimated to be 0.004 mm. What are the upper and lower specification limits for this product? The process is currently operating at a

mean thickness of 2.50 mm. (a) What is the Cp for this process? (b) About what percent of all units of this liner will meet specifications? Does this meet the technical definition of Six Sigma?

(a) LSL = 2.48 mm, USL = 2.52 mm. Cp = (2.52 – 2.48)/(6*0.004) = 1.67. (b) Each specification limit lies 5 standard deviations from the centerline, so practically 100 percent of units will meet specifications. However, this percentage is not quite as high as Six Sigma would call for. (Process capability, moderate) {AACSB: Analytic Skills}

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133.The specifications for a manifold gasket that installs between two engine parts calls for a thickness of 2.500 mm + .020 mm. The standard deviation of the process is estimated to be 0.004 mm. What are the upper and lower specification limits for this product? The process is currently operating at a

mean thickness of 2.50 mm. (a) What is the Cp for this process? (b) The purchaser of these parts requires a capability index of 1.50. Is this process capable? Is this process good enough for the supplier? (c) If the process mean were to drift from its setting of 2.500 mm to a new mean of 2.497, would the process still be good enough for the supplier's needs?

(a) LSL = 2.48 mm, USL = 2.52 mm. Cp = (2.52 – 2.48)/(6*0.004) = 1.67. (b) Yes to both parts of the question. (c) The Cpk index is now relevant, and its value is the lesser of 1.917 and 1.417. The process is still capable, but not to the supplier's needs. (Process capability, moderate)

{AACSB: Analytic Skills}

134.The specification for a plastic liner for concrete highway projects calls for a thickness of 6.0 mm ± 0.1 mm. The standard deviation of the process is estimated to be 0.02 mm. What are the upper and lower specification limits for this product? The process is known to operate at a mean thickness of

6.03 mm. What is the Cp and Cpk for this process? About what percent of all units of this liner will meet specifications?

LSL = 5.9 mm, USL = 6.1 mm. Cp is (6.1-5.9)/6(.02) = 1.67. Cpk is the lesser of (6.1-

6.03)/(3*0.02) = 1.17 and (5.9 - 6.03)/(3*0.02) = 2.17; therefore, 1.17. The upper specification limit lies about 3 standard deviations from the centerline, and the lower specification limit is further away, so practically all units will meet specifications. (Process capability, moderate) {AACSB: Analytic Skills}

135.The specification for a plastic handle calls for a length of 6.0 inches ± .2 inches. The standard deviation of the process is estimated to be 0.05 inches. What are the upper and lower specification limits for this product? The process is known to operate at a mean thickness of 6.1 inches. What is

the Cp and Cpk for this process? Is this process capable of producing the desired part?

LSL = 5.8 inches, USL = 6.2 inches. Cp is (6.2-5.8)/6(.05) = 1.33. Cpk is the lesser of (6.2-

6.1)/(3*0.05) = .67 and (5.8 - 6.1)/(3*0.02) = 2.00; therefore, .67. The process is capable based

upon the Cp. However, the process is not centered (based upon its Cpk) and based upon its current center is not producing parts that are of an acceptable quality. (Process capability, moderate) {AACSB: Analytic Skills}

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136.In the table below are selected values for the OC curve for the acceptance sampling plan n=210, c=6. Upon failed inspection, defective items are replaced. Calculate the AOQ for each data point. (You may assume that the population is much larger than the sample.) Plot the AOQ curve. At approximately what population defective rate is the AOQ at its worst? Explain how this happens. How well does this plan meet the specifications of AQL=0.015, α=0.05; LTPD=0.05, β =0.10? Discuss.

Population percent defective		Probability of acceptance
0.00	1.00000
0.01	0.99408
0.02	0.86650
0.03	0.55623
0.04	0.26516
0.05	0.10056
0.06	0.03217
0.07	0.00905
0.08	0.00231
0.09	0.00054
0.10	0.00012
The plan meets the α and the β specification fairly well.
				AOQ
Population percent defective		Probability of acceptance
0.00		1.000		0.0000
0.01		0.994		0.0099
0.015		0.958		0.0144	At AQL
0.02		0.867		0.0173	maximum
0.03		0.558		0.0167
0.04		0.267		0.0107
0.05		0.102		0.0051	At LTPD
0.06		0.033		0.0020
0.07		0.009		0.0006
0.08		0.002		0.0002
0.09		0.001		0.0001

(Acceptance sampling, moderate) {AACSB: Analytic Skills}

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137.In the table below are selected values for the OC curve associated with the acceptance sampling plan n=50, c=1. (Watch out--the points are not evenly spaced.) Assume that upon failed inspection, defective items are replaced. Calculate the AOQ for each data point. (You may assume that the population is much larger than the sample.) Plot the AOQ curve. At approximately what population defective rate is the AOQ at its worst? Explain how this happens. How well does this plan meet the specifications of AQL=0.0050, α=0.05; LTPD=0.05, ·β =0.10? Discuss.

Population percent defective	Probability of acceptance
0.005	0.97387
0.01	0.91056
0.02	0.73577
0.03	0.55528
0.04	0.40048
0.05	0.27943
0.06	0.19000
0.08	0.08271

This plan does not meet the specification very well. At .005 defective, the probability of acceptance is not 95% but over 97. At 0.05 defective, the acceptance rate is not 5% but 28.

Population percent defective	Probability of acceptance	AOQ
0.005	0.97387	0.004869	at AQL
0.01	0.91056	0.009106
0.02	0.73577	0.014715
0.03	0.55528	0.016658	maximum
0.04	0.40048	0.016019
0.05	0.27943	0.013972	at LTPD
0.06	0.19000	0.0114
0.08	0.08271	0.006617

(Acceptance sampling, moderate) {AACSB: Analytic Skills}

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138.A bank’s manager has videotaped 20 different teller transactions to observe the number of mistakes being made. Ten transactions had no mistakes, five had one mistake and five had two mistakes. Compute proper control limits at the 90% confidence level.

A c-chart should be used, and from Table S6.2, the z-value = 1.65. The mean c-bar = [10(0) + 5(1) + 5(2)]/20 = 0.75.

UCLc = 0.75 +1.65 0.75 = 2.18.

LCLc = 0.75 −1.65 0.75 = −0.68 (or 0).

(Statistical process control (SPC), moderate) {AACSB: Analytic Skills}

139.A department chair wants to monitor the percentage of failing students in classes in her department. Each class had an enrollment of 50 students last spring. The number of failing students in the 10 classes offered that term were 1, 4, 2, 0, 0, 0, 0, 0, 0, and 3, respectively. Compute the control limits for a p-chart at the 95% confidence level. Is the process in control?

From Table S6.2, the z-value = 1.96.

The mean p-bar = [1+4+2+0+0+0+0+0+0+3]/(50×10) = 0.02.

σ^ =	0.02(1−0.02)	= 0.0198
p	50

UCLp = 0.02 + 1.96(.0198) = 0.0589.

LCLp = 0.02 − 1.96(.0198) = −0.0189 (or 0).

Since the percent defects in classes 2 and 10 both exceeded 5.89%, the percentage of failing students is not in statistical control. The department chair should investigate.

(Statistical process control (SPC), moderate) {AACSB: Analytic Skills}

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CHAPTER 7: PROCESS STRATEGY

TRUE/FALSE

1.Dell's approach to personal computer manufacturing is to use a product focus, which gives the company its low-cost competitive advantage.

False (Global company profile, easy)

2.A firm's process strategy is its approach to transforming resources into goods and services.

True (Introduction, easy)

3.Intermittent processes are organized around processes.

True (Four process strategies, easy)

4.In process-focused facilities, equipment utilization is low.

True (Four process strategies, moderate)

5.The typical full-service restaurant uses a product-focused process.

False (Four process strategies, moderate)

6.Harley-Davidson, because it has so many possible combinations of products, utilizes the process strategy of mass customization.

False (Four process strategies, moderate)

7.A value-stream map includes both (1) inventory quantities, and (2) symbols for customers and suppliers.

True (Process analysis and design, moderate)

8.The assembly line is a classic example of a repetitive process.

True (Four process strategies, easy)

9.One essential ingredient of mass customization is modular design.

True (Four process strategies, moderate)

10.The tool that calculates which process has the lowest cost at any specified production volume is a crossover chart.

True (Four process strategies, moderate)

11.The term focused processes refers to the quest for increased efficiency, whether in goods or services, that results from specialization.

True (Four process strategies, moderate)

12.Service blueprinting is a process analysis technique that focuses on the customer and the provider's interaction with the customer.

True (Process analysis and design, moderate)

13.Activity times should not be included in a service blueprint.

False (Process analysis and design, moderate)

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14.A process map with the addition of a time axis becomes a process chart.

False (Process analysis and design, moderate)

15.Time-function mapping is a flow diagram with time added to the horizontal axis.

True (Process analysis and design, moderate)

16.Process maps use distance, but not time, to show the movement of material, product, or people through a process.

False (Process analysis and design, moderate)

17.Professional services typically require low levels of labor intensity.

False (Service process design, moderate)

18.An example of the postponement strategy for improving service productivity is having the customer wait until you have sufficient time to serve the customer.

False (Service process design, moderate)

19.Process control is the use of information technology to monitor and control a physical process.

True (Production technology, easy) {AACSB: Use of IT}

20.One use of camera-and-computer-based vision systems is to replace humans doing tedious and error-prone visual inspection activities.

True (Production technology, easy) {AACSB: Use of IT}

21.Automated storage and retrieval systems are commonly used in distribution facilities of retailers.

True (Production technology, moderate) {AACSB: Use of IT}

22.Flexible manufacturing systems, because of easily changed control programs, are able to perform such tasks as manufacturing one-of-a-kind parts economically.

True (Production technology, moderate) {AACSB: Use of IT}

23.Production technology has had a major impact on services, but as yet there has been little reduction in service labor requirements.

False (Technology in services, moderate) {AACSB: Use of IT}

24.Optical checkout scanners and ATMs are examples of technology's impact on services.

True (Technology in services, moderate) {AACSB: Use of IT}

25.Successful process redesign focuses on departmental areas where small, continuous improvements can be made.

False (Process redesign, moderate)

26.Processes can be environmentally friendly and socially responsible while still contributing to profitable strategies.

True (Ethics and environmentally friendly processes, easy) {AACSB: Ethical Reasoning}

27.In selecting new equipment and technology, decision-makers look for flexibility—the ability to respond with little penalty in time, cost, or customer value.

True (Selection of equipment and technology, moderate)

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MULTIPLE CHOICE

28.Which of the following statements regarding Dell Computer is false?

a.Dell is a practitioner of the mass customization process.

b.Dell builds its computers overseas in order to gain a low-cost advantage.

c.Dell keeps very little inventory of finished goods.

d.Dell utilizes a global supply chain, but assembles its computers in the U.S.

e.Dell's research focuses on manufacturing issues, not computer part design.

b(Global company profile, moderate)

29.An organization's process strategy

a.will have long-run impact on efficiency and flexibility of production

b.is the same as its transformation strategy

c.must meet various constraints, including cost

d.is concerned with how resources are transformed into goods and services

e.All of the above are true.

e (Introduction, moderate)

30.A job shop is an example of a(n)

a.repetitive process

b.continuous process

c.line process

d.intermittent process

e.specialized process

d (Four process strategies, moderate)

31.Three types of processes are

a.goods, services, and hybrids

b.manual, automated, and service

c.process focus, repetitive focus, and product focus

d.modular, continuous, and technological

e.input, transformation, and output

c (Four process strategies, moderate)

32.Which of the following industries is likely to have low equipment utilization?

a.auto manufacturing

b.commercial baking

c.television manufacturing

d.chemical processing

e.restaurants

e (Four process strategies, moderate)

33.A product-focused process is commonly used to produce

a.high-volume, high-variety products

b.low-volume, high-variety products

c.high-volume, low-variety products

d.low-variety products at either highor low-volume

e.high-volume products of either highor low-variety

c(Four process strategies, moderate)

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34.Which one of the following products is most likely made in a job shop environment?

a.a daily newspaper

b.paper forms

c.television sets

d.cigarettes

e.canned vegetables

b (Four process strategies, moderate)

35.Which of the following products is likely to be assembled on a repetitive process line?

a.automobiles

b.personal computers

c.dishwashers

d.television sets

e.all of the above

e (Four process strategies, moderate)

36.An assembly line is an example of a

a.product-focused process

b.process-focused process

c.repetitive process

d.line process

e.specialized process

c (Four process strategies, moderate)

37.Standard Register

a.has dozens of U.S. plants in its Forms Division

b.groups people and machines into departments that perform specific activities

c.utilizes a product strategy to keep production volume high

d.obtains its low-cost advantage by not spending money on CAD systems

e.obtains its low-cost advantage by specializing in a relatively small number of products

b(Four process strategies, moderate)

38.Which of the following transformations generally has the highest equipment utilization?

a.process-focused process

b.repetitive process

c.product-focused process

d.specialized process

e.modular process

c (Four process strategies, moderate)

39.Harley Davidson

a.utilizes job shops to make each of its modules

b.uses product focused manufacturing

c.uses a large number of modules to build a small number of different bikes

d.uses work cells to feed its assembly line

e.All of the above are true.

d (Four process strategies, moderate)

159

40.Which of the following is false regarding repetitive processes?

a.They use modules.

b.They allow easy switching from one product to the other.

c.They are the classic assembly lines.

d.They have more structure and less flexibility than a job shop layout.

e.They include the assembly of basically all automobiles.

b (Four process strategies, moderate)

41.When done correctly, mass customization

a.increases pressure on supply chain performance

b.helps eliminate the guesswork that comes with sales forecasting

c.drives down inventories

d.increases pressure on scheduling

e.all of the above

e (Four process strategies, moderate)

42.Which of the following phrases best describes product focus?

a.low volume, high variety

b.finished goods are usually made to order

c.processes are designed to perform a wide variety of activities

d.high fixed costs, low variable costs

e.raw material inventories are low relative to the value of the product

d(Four process strategies, difficult)

43.Which of the following phrases best describes process focus?

a.low volume, high variety

b.finished goods are usually made to a forecast and stored

c.operators are modestly skilled

d.high fixed costs, low variable costs

e.raw material inventories are high relative to the value of the product

a(Four process strategies, difficult)

44.Which of the following characteristics best describes repetitive focus?

a.It uses sophisticated scheduling to accommodate custom orders.

b.Its output is a standardized product produced from modules.

c.It is too expensive when volumes are low or flexibility is required.

d.It is widely used for the manufacture of steel.

e.Its costs are often known only after a job is done.

b (Four process strategies, difficult)

45.Utilization in process-oriented facilities is frequently low because

a.the postponement strategy for improving service productivity is being used

b.scheduling in process-oriented facilities is not very complex

c.with high fixed costs, utilization is not very important

d.excess capacity for peak demands is desirable

e.low raw material inventories cause machines to be idled

d (Four process strategies, moderate)

160