Deck 12: Statistically Based Quality Improvement for Attributes

Question 1

A quality engineer notes that a process produces data that are binomial and has been obtained using a sample space that is not constant. The primary interest of the process manager is in the number of discrepancies per part. An appropriate control chart to use would be a(n)________.

A)np chart
B)p chart
C)c chart
D)u chart
E)d chart

Answer 1

D

Question 2

Sensory attributes relate to whether or not a particular product or service performs as it is supposed to.

Answer 2

False

Question 3

A painter paints a wall and when too much paint is applied, drips result. In the language of attribute charts, the drips are ________.

A)defectives
B)defects
C)variables
D)critical
E)temporal

Answer 3

B

Question 4

Customer-based attributes are internal and engineering-oriented.

Question 5

A quality engineer notes that a process produces data that are binomial and has been obtained using a sample space that is not constant. The primary interest of the process manager is in the percentage of bad parts. An appropriate control chart to use would be a(n)________.

A)np chart
B)p chart
C)c chart
D)u chart
E)d chart

Question 6

State the five types of attributes.

Question 7

An attribute is a continuous measurement such as weight, height, or volume.

Question 8

The atmosphere and other aspects of a customer's experience in a hotel would be examples of sensory attributes.

Question 9

A painting contractor wishes to compare the work done by several painters in several rooms of varying sizes. If the contractor is concerned about drips and missed spots, an np chart would be the logical choice.

Question 10

________ attributes relate to time.

A)Structural
B)Sensory
C)Performance
D)Temporal
E)Tactile

Question 11

Production-related attributes are more important to quality managers than customer-based attributes.

Question 12

A quality engineer notes that a process produces data that are binomial and has been obtained using a sample space that is constant. The primary interest of the process manager is in the percentage of bad parts. An appropriate control chart to use would be a(n)________.

A)p chart
B)r chart
C)c chart
D)u chart
E)d chart

Question 13

________ attributes relate to senses of touch, smell, taste, and sound.

A)Structural
B)Sensory
C)Performance
D)Consensual
E)Ethical

Question 14

________ attributes relate to the physical characteristics of a particular product or service.

A)Structural
B)Sensory
C)Performance
D)Temporal
E)Ethical

Question 15

Attributes that are more internal and engineering-oriented are called ________ attributes.

A)structural
B)sensory
C)performance
D)customer-based
E)production-related

Question 16

________ attributes answer whether a service provider is empathetic or if their accounting systems report properly.

A)Structural
B)Sensory
C)Performance
D)Temporal
E)Ethical

Question 17

Attribute charts are developed and interpreted the same way as variables charts.

Question 18

________ attributes relate to whether or not a particular product or service performs as it is supposed to.

A)Structural
B)Sensory
C)Performance
D)Temporal
E)Ethical

Question 19

The first step in developing an attribute process chart is to ________.

A)determine whether the critical product characteristic is a variable or an attribute
B)establish control limits
C)identify critical product characteristics
D)identify critical operations where process inspection might be needed
E)select the appropriate process chart from the many types of charts

Question 20

Structural attributes have to do with physical characteristics of a particular product or service.

Question 21

A producer of contact lenses regularly takes samples of 100 lenses and inspects them for scratches. If a lens has a single scratch, it cannot be sold. The results of 10 samples are shown. What sample is out of control?

A)2
B)4
C)6
D)8
E)none of the above

Question 22

A unit that, as a whole, is not acceptable or does not meet performance requirements is a(n)________.

A)defect
B)defective
C)flaw
D)mistake
E)error

Question 23

Defectives are monitored using ________.

A)c charts
B)g charts
C)u charts
D)p charts
E)d charts

Question 24

A manufacturer of FAX machines checks samples of 50 units for functionality at the conclusion of the assembly process. The results of 10 samples are shown below: What sample is out of control?

A)1
B)2
C)3
D)4
E)none of the above

Question 25

An insurance claims department employs 10 claims adjusters who spend all day verifying that forms are valid and have been completed correctly. Forms with mistakes are useless and must be returned to the adjuster who must contact the customer again and resubmit the claim. The supervisor reviews two claims processed by each employee to verify that the process is working at acceptable levels.
How should the process be monitored? Explain your reasoning.

Question 26

Determining whether a critical product characteristic is a variable or attribute is one of the steps in developing a process chart.

Question 27

A winemaker tastes several 750 ml bottles of varying vintages. A good choice for such a test would be a c chart.

Question 28

A producer of contact lenses regularly takes samples of 100 lenses and inspects them for scratches. If a lens has a single scratch, it cannot be sold. The results of 10 samples are shown. What is the average proportion defective?

A)0.012
B)0.014
C)0.020
D)0.028
E)0.035

Question 29

The producers of the Yugo automobile periodically inspect samples of 80 hoods for dents and scratches. A single flaw in a hood renders it unsuitable for installation in one of their fine automobiles. The results of the last 10 samples are shown. Calculate the standard error, snp, for the np chart.

A)7.75
B)0.10
C)0.31
D)2.78
E)2.95

Question 30

Describe the differences between a defect and a defective. Provide an example of each and identify the types of process charts that would monitor defects and defectives.

Question 31

An irregularity or problem with a larger unit is a(n)________.

A)defect
B)defective
C)flaw
D)mistake
E)error

Question 32

A parks and recreation worker counts the number of paint drips on each standard size park bench. The results from the last 10 benches are shown. If the Parks Department decides to make a c chart, what bench number is out of control?

A)1
B)3
C)5
D)7
E)none of the above

Question 33

Which of the following is an example of a statistic based on an attribute?

A)s (standard deviation)
B)R (range)
C)p (proportion defective)
D)MR (moving range)
E)X bar (process population average)

Question 34

What are attribute charts used for and how do they work?

Question 35

A p chart can be used whether or not there is a constant sample size.

Question 36

What are the steps required to develop an attribute control chart?

Question 37

The producers of the Yugo automobile periodically inspect samples of 80 hoods for dents and scratches. A single flaw in a hood renders it unsuitable for installation in one of their fine automobiles. The results of the last 10 samples are shown. What sample is out of control?

A)1
B)3
C)5
D)4
E)10

Question 38

Which of the following is not used for monitoring defects or defectives?

A)p charts
B)np charts
C)u charts
D)c charts
E)r charts

Question 39

A defect is an irregularity or problem with a larger unit.

Question 40

A manufacturer of FAX machines checks samples of 50 units for functionality at the conclusion of the assembly process. The results of 10 samples are shown. What is the average proportion defective?

A)0.07
B)0.14
C)0.21
D)0.28
E)0.35

Question 41

What is a u chart and how is it similar to or different than a c chart?

Question 42

The vertical axis on the bathtub function is ________.

A)failure rate
B)time
C)predicted life
D)design reliability
E)useful life

Question 43

The p chart is a process chart that is used to graph the proportion of items in a sample that are defective.

Question 44

A system is composed of three components. Two of the items are in parallel and have reliabilities of 0.95 and 0.90. The third item has a reliability of 0.98 and this item is in series with the first combination. What is the overall system reliability?

A)0.995
B)0.985
C)0.975
D)0.965
E)0.955

Question 45

A producer of contact lenses regularly takes samples of 100 lenses and inspects them for scratches. If a lens has a single scratch, it cannot be sold. The results of 10 samples are shown. What are the lower and upper 3-sigma control limits?

A)(-0.021, 0.012)
B)(-0.021, 0.000)
C)(0.012, 0.035)
D)(0.000, 0.035)
E)(0.000, 0.049)

Question 46

The u chart is a graph of the number of defects per unit.

Question 47

The producers of the Yugo automobile periodically inspect samples of 80 hoods for dents and scratches. A single flaw in a hood renders it unsuitable for installation in one of their fine automobiles. The results of the last 10 samples are shown.. What are the lower and upper control limits for the np chart?

A)(-8.35, 2.8)
B)(2.8, 8.35)
C)(0.3, 17.1)
D)(8.7, 17.1)
E)(0.4, 8.7)

Question 48

A manufacturer of FAX machines checks samples of 50 units for functionality at the conclusion of the assembly process. The results of 10 samples are shown. What are the lower and upper 3-sigma control limits?

A)(-0.01, 0.09)
B)(-0.01, 0.00)
C)(-0.01, 0.29)
D)(0.00, 0.09)
E)(0.00, 0.29)

Question 49

A parks and recreation worker counts the number of paint drips on each standard size park bench. The results from the last 10 benches are shown. If the Parks Department decides to make a c chart, what should the center line be?

A)6.9
B)8.4
C)9.2
D)10.7
E)11.3

Question 50

An np chart can be used whether or not the sample sizes are the same.

Question 51

A parks and recreation worker counts the number of paint drips on each standard size park bench. The results from the last 10 benches are shown. If the Parks Department decides to make a c chart, what should the lower and upper 3-sigma control limits be?

A)(-9.2, 9.2)
B)(0.0, 20)
C)(0.1, 18.3)
D)(3.1, 13.1)
E)(3.1, 18.3)

Question 52

The reliability model that shows that products are more likely to fail either very early in their useful life or very late in their useful life is called the ________.

A)half-moon hazard function
B)saucer-shaped hazard function
C)half-circle hazard function
D)cone-shaped hazard function
E)bathtub-shaped hazard function

Question 53

The shape of the process line in a p chart and an np chart plot is always identical if the same data are used.

Question 54

The lower control limit for a p chart cannot be lower than zero.

Question 55

System unreliability is increased with ________.

A)a redundant system
B)a parallel system
C)a backup system
D)high reliability components
E)low reliability components

Question 56

The horizontal axis on the bathtub function is ________.

A)failure rate
B)time
C)useful life
D)design reliability
E)predicted life

Question 57

The np chart is a graph of the number of defectives in a subgroup.

Question 58

Reliability models assume statistical independence between failure events. This means that ________.

A)components do not fail
B)if one component fails, the entire system fails
C)parallel systems are unnecessary
D)the failure of one component does not influence another to fail
E)series systems are unnecessary

Question 59

The producers of the Yugo automobile periodically inspect samples of 80 hoods for dents and scratches. A single flaw in a hood renders it unsuitable for installation in one of their fine automobiles. The results of the last 10 samples are shown.. What is the center line for the np chart?

A)2.4
B)5.8
C)7.2
D)8.7
E)10.1

Question 60

What is a np chart and how is it similar to or different than a p chart?

Question 61

A system is composed of three components in series having reliabilities of 0.99, 0.95, and 0.90. What is the overall system reliability?

A)0.95
B)0.90
C)0.85
D)0.80
E)0.75

Question 62

What is the useful life in hours for a product having a reliability of 0.999 and a failure rate of 0.015 failures per hour?

A)400
B)420
C)440
D)460
E)480

Question 63

A system is composed of three components in series having reliabilities of 0.85, 0.92, and 0.90. What is the overall system reliability?

A)0.90
B)0.85
C)0.80
D)0.75
E)0.70

Question 64

A system is to be composed of 10 identical components in series. What is the lowest reliability component that can be used in order to have an overall system reliability of 0.90?

A)0.99
B)0.98
C)0.97
D)0.96
E)0.95

Question 65

What is the approximate useful life in hours for a product having a reliability of 0.9978 and a failure rate of 0.001 failures per hour?

A)6120
B)5600
C)5000
D)4400
E)3800

Question 66

What is the system availability for something that has a mean time between failures of 50 hours and needs an average of 1 hour to repair when it does fail?

A)0.98
B)0.92
C)0.86
D)0.80
E)0.74

Question 67

What is the reliability of a product with a failure rate of 0.015 per operating hour and a useful life of 250 hours?

A)0.14
B)0.12
C)0.88
D)0.98
E)0.02

Question 68

A system is composed of three components in series having reliabilities of 0.99, 0.98, and 0.97. What is the overall system reliability?

A)0.97
B)0.96
C)0.95
D)0.94
E)0.93

Question 69

A system is to be composed of 5 identical components in series. What is the lowest reliability component that can be used in order to have an overall system reliability of 0.90?

A)0.98
B)0.97
C)0.96
D)0.95
E)0.94

Question 70

Two components of reliability 0.95 are in parallel and this subsystem is connected in series to a component with a reliability of 0.90. The overall system reliability is ________.

A)0.82
B)0.84
C)0.86
D)0.88
E)0.90

Question 71

What is the reliability of a product with a failure rate of 0.001 per operating hour and a useful life of 1500 hours?

A)0.14
B)0.22
C)0.50
D)0.78
E)0.86

Question 72

Two components of reliability 0.90 are in parallel and this subsystem is connected in series to a component with a reliability of 0.95. The overall system reliability is ________.

A)0.93
B)0.94
C)0.95
D)0.96
E)0.97

Question 73

Fifty defibrillators are tested for 48 hours per machine. Of all the machines tested, 2 experience malfunctions during the test. What is the failure rate for the machines?

A)0.004
B)0.042
C)0.01
D)0.008
E)0.0008

Question 74

Two components of reliability 0.95 are in parallel and this subsystem is connected in series to a component with a reliability of 0.95. The overall system reliability is ________.

A)0.93
B)0.94
C)0.95
D)0.96
E)0.97

Question 75

A system is to be composed of 4 identical components in series. What is the lowest reliability component that can be used in order to have an overall system reliability of 0.85?

A)0.93
B)0.94
C)0.95
D)0.96
E)0.97

Question 76

What is the system availability for something that has a mean time between failures of 168 hours and needs an average of 48 hours to repair when it does fail?

A)0.98
B)0.93
C)0.88
D)0.83
E)0.78

Question 77

Fifty crash helmets are tested for one hundred hours per helmet. Of all the helmets tested, only one experiences a malfunction during the test. What is the failure rate for the helmets?

A)0.0002
B)0.002
C)0.004
D)0.0008
E)0.016

Question 78

What is the useful life in hours for a product having a reliability of 0.985 and a failure rate of 0.015 failures per hour?

A)120
B)200
C)280
D)360
E)440

Question 79

What is the system availability for something that has a mean time between failures of 100 hours and needs an average of 4 hours to repair when it does fail?

A)0.98
B)0.92
C)0.96
D)0.90
E)0.84

Question 80

What is the reliability of a product with a failure rate of 0.002 per operating hour and a useful life of 1000 hours?

A)0.14
B)0.22
C)0.50
D)0.78
E)0.86