# Quiz 10: Quality Control

Statistics

Q 1Q 1

Approving the effort that occurs during the production process is known as acceptance sampling.

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True False

False

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True False

False

Q 3Q 3

The traditional view is that the optimum level of inspection occurs when we catch at least 98.6 percent of the defects.

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True False

False

Q 4Q 4

The traditional view is that the optimum level of inspection minimizes the sum of inspection costs and the cost of passing defectives.

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True False

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True False

Q 6Q 6

High-cost, low-volume items often require careful inspection since we may have large costs associated with passing defectives.

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True False

Q 7Q 7

Low-cost, high-volume items often require more intensive inspection than other types of items.

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True False

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True False

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True False

Q 10Q 10

The amount of inspection we choose can range from no inspection at all to inspecting each item numerous times.

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True False

Q 11Q 11

The amount of inspection needed is governed by the costs of inspection and the expected costs of passing defective items.

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True False

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True False

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True False

Q 14Q 14

If a point on a control chart falls outside one of the control limits, this suggests that the process output is nonrandom and should be investigated.

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True False

Q 15Q 15

An x-bar control chart can only be valid if the underlying population it measures is a normal distribution.

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True False

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True False

Q 17Q 17

An R value of zero (on a range chart)means that the process must be in control since all sample values are equal.

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True False

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True False

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True False

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True False

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True False

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True False

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True False

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True False

Q 25Q 25

Control limits used on process control charts are specifications established by design or customers.

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True False

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True False

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True False

Q 28Q 28

The output of a process may not conform to specifications even though the process may be statistically "in control."

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True False

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True False

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True False

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True False

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True False

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True False

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True False

Q 35Q 35

The purpose of quality control is making sure that processes are performing in an acceptable manner.

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True False

Q 36Q 36

The primary purpose of statistical process control is to detect a defective product before it is shipped to a customer.

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True False

Q 37Q 37

The Taguchi loss function suggests that the capability ratio can be improved by extending the spread between LCL and UCL.

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True False

Q 38Q 38

The variation of a sampling distribution isless than the variation of the underlying process distribution.

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True False

Q 39Q 39

The sampling distribution can be assumed to be approximately normal even when the underlying process distribution is not normally distributed.

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True False

Q 40Q 40

Approximately 99.7 percent of sample means will fall within plus or minus two standard deviations of the process mean if the process is under control.

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True False

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True False

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True False

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True False

Q 44Q 44

The number of defective parts in a sample is an example of variable data because it will "vary" from one sample to another.

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True False

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True False

Q 46Q 46

When a process is not centered, its capability is measured in a slightly different way. The symbol for this case is C

_{pk}.Free

True False

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True False

Q 48Q 48

Statistical process control charts are not really used to fix quality so much as they are used to
A)highlight when processes are not capable.
B)point out when random variation is present.
C)alert when corrective action is needed.
D)monitor the quality of incoming shipments or outgoing finished goods.
E)initiate team-building exercises.

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Multiple Choice

Q 49Q 49

The assurance that processes are performing in an acceptable manner is the focus of
A)variability analysis.
B)inspection.
C)capability assessment.
D)quality control.
E)acceptance sampling.

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Multiple Choice

Q 50Q 50

Inspection is a(n)_____ activity.
A)prevention.
B)capability analysis.
C)flawless
D)corrective.
E)appraisal.

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Multiple Choice

Q 51Q 51

Acceptance sampling, when it is used, is used
(I)before production.(II)during production.(III)after production.
A)I only
B)I and III only
C)I and II only
D)II and III only
E)I, II, and III

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Multiple Choice

Q 52Q 52

The amount of inspection needed depends on _____ and _____.
A)the amount of automation; the reliability of inspectors
B)the quality of the supplier; the target market of the process
C)the costs of inspection; the costs of passing on defective items
D)where in the process the inspection occurs; the volume of the process
E)the cost of the item being inspected; the use of the item being inspected

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Multiple Choice

Q 53Q 53

The greater the volume of the process being targeted for inspection, the more attractive _____ inspection is.
A)monitored
B)controlled
C)periodic
D)variable
E)automated

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Multiple Choice

Q 54Q 54

Which of the following quality control sample statistics indicates a quality characteristic that is an attribute?
A)mean
B)variance
C)standard deviation
D)range
E)proportion

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Multiple Choice

Q 55Q 55

A time-ordered plot of representative sample statistics is called a(n)
A)Gantt chart.
B)simo chart.
C)control chart.
D)up-down matrix.
E)standard deviation table.

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Multiple Choice

Q 56Q 56

A control chart used to monitor the process mean is the
A)p-chart.
B)R-chart.
C)x-bar chart.
D)c-chart.
E)Gantt chart.

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Multiple Choice

Q 57Q 57

A control chart used to monitor the fraction of defectives generated by a process is the
A)p-chart.
B)R-chart.
C)x-bar chart.
D)c-chart.
E)Gantt chart.

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Multiple Choice

Q 58Q 58

A p-chart would be used to monitor
A)average shrinkage.
B)dispersion in sample data.
C)the fraction defective.
D)the number of defects per unit.
E)the range of values.

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Multiple Choice

Q 59Q 59

A c-chart is used for
A)means.
B)ranges.
C)percent defective.
D)fraction defective per unit.
E)number of defects per unit.

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Multiple Choice

Q 60Q 60

A control chart used to monitor the number of defects per unit is the
A)p-chart.
B)R-chart.
C)x-bar chart.
D)c-chart.
E)Gantt chart.

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Multiple Choice

Q 61Q 61

A point which is outside of the lower control limit on an R-chart
A)is an indication that no cause of variation is present.
B)should be ignored because it signifies better-than-average quality.
C)should be investigated because an assignable cause of variation might be present.
D)should be ignored unless another point is outside that limit.
E)is impossible since the lower limit is always zero.

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Multiple Choice

Q 62Q 62

If a process is performing as it should, it is still possible to obtain observations which are outside of which limits?
(I)tolerances(II)control limits(III)process variability
A)I
B)II
C)I and II
D)II and III
E)I, II, and III

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Multiple Choice

Q 63Q 63

Which of the following relationships must always be incorrect?
A)Tolerances > process variability > control limits
B)Process variability > tolerances > control limits
C)Tolerances > control limits > process variability
D)Process variability > control limits > tolerances
E)Process variability < tolerances < control limits

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Multiple Choice

Q 64Q 64

Which of the following is not a step in the control process?
A)Define what is to be controlled.
B)Compare measurements to a standard.
C)100 percent inspection.
D)Take corrective action if necessary.
E)Evaluate corrective action.

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Multiple Choice

Q 65Q 65

The probability of concluding that assignable variation exists when only random variation is present is
(I)the probability of a Type I error.(II)known as the alpha risk.(III)highly unlikely.(IV)the sum of probabilities in the two tails of the normal distribution.
A)I and II
B)I and IV
C)II and III
D)I, II, and IV
E)I, III, and IV

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Multiple Choice

Q 66Q 66

_____ variation is a variation whose cause can be identified.
A)Assignable
B)Controllable
C)Random
D)Statistical
E)Theoretical

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Multiple Choice

Q 67Q 67

A plot below the lower control limit on the range chart
(I)should be ignored since lower variation is desirable.(II)may be an indication that process variation has decreased.(III)should be investigated for assignable cause.
A)I and II
B)I and III
C)II and III
D)II only
E)I, II, and III

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Multiple Choice

Q 68Q 68

A shift in the process mean for a measured characteristic would most likely be detected by a
A)p-chart.
B)x-bar chart.
C)c-chart.
D)R-chart.
E)s-chart.

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Multiple Choice

Q 69Q 69

The range chart ( R-chart)is most likely to detect a change in
A)proportion.
B)mean.
C)number defective.
D)variability.
E)sample size.

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Multiple Choice

Q 70Q 70

The traditional view is that the optimum level of inspection is where the
A)cost of inspection is minimum.
B)cost of passing defectives is minimum.
C)total cost of inspection and defectives is maximum.
D)total cost of inspection and defectives is minimum.
E)difference between inspection and defectives costs is minimum.

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Multiple Choice

Q 71Q 71

The purpose of control charts is to
A)estimate the proportion of output that is acceptable.
B)weed out defective items.
C)determine if the output is within tolerances/specifications.
D)distinguish between random variation and assignable variation in the process.
E)provide meaningful work for quality inspectors.

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Multiple Choice

Q 72Q 72

The process capability index (C

_{pk})may mislead if (I)the process is not stable.(II)the process output is not normally distributed.(III)the process is not centered. A)I and II B)I and III C)II and III D)II only E)I, II, and IIIFree

Multiple Choice

Q 73Q 73

A time-ordered plot of sample statistics is called a(n)_____ chart.
A)statistical
B)inspection
C)control
D)simo
E)limit

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Multiple Choice

Q 74Q 74

Consider the following information
The number of runs up and down for the preceding data is
A)3.
B)4.
C)5.
D)6.
E)none of these.

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Multiple Choice

Q 75Q 75

Consider the following information
The number of runs above and below the sample median is:
A)3.
B)4.
C)5.
D)6.
E)none of these.

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Multiple Choice

Q 76Q 76

The following data occurs chronologically from left to right
The number of runs up and down is:
A)2.
B)3.
C)4.
D)5.
E)none of these.

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Multiple Choice

Q 77Q 77

A design engineer wants to construct a sample mean chart for controlling the service life of a halogen headlamp his company produces. He knows from numerous previous samples that this service life is normally distributed with a mean of 500 hours and a standard deviation of 20 hours. On three recent production batches, he tested service life on random samples of four headlamps, with these results
What is the sample mean service life for sample 2?
A)460 hours
B)495 hours
C)500 hours
D)515 hours
E)525 hours

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Multiple Choice

Q 78Q 78

A design engineer wants to construct a sample mean chart for controlling the service life of a halogen headlamp his company produces. He knows from numerous previous samples that when this service life is in control it is normally distributed with a mean of 500 hours and a standard deviation of 20 hours. On three recent production batches, he tested service life on random samples of four headlamps, with these results
What is the mean of the sampling distribution of sample means when the service life is in control?
A)250 hours
B)470 hours
C)495 hours
D)500 hours
E)515 hours

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Multiple Choice

Q 79Q 79

A design engineer wants to construct a sample mean chart for controlling the service life of a halogen headlamp his company produces. He knows from numerous previous samples that this service life is normally distributed with a mean of 500 hours and a standard deviation of 20 hours. On three recent production batches, he tested service life on random samples of four headlamps, with these results
What is the standard deviation of the sampling distribution of sample means for whenever service life is in control?
A)5 hours
B)6.67 hours
C)10 hours
D)11.55 hours
E)20 hours

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Multiple Choice

Q 80Q 80

A design engineer wants to construct a sample mean chart for controlling the service life of a halogen headlamp his company produces. He knows from numerous previous samples that this service life is normally distributed with a mean of 500 hours and a standard deviation of 20 hours. On three recent production batches, he tested service life on random samples of four headlamps, with these results
If he uses upper and lower control limits of 520 and 480 hours, what is his risk (alpha)of concluding that service life is out of control when it is actually under control (Type I error)?
A)0.0026
B)0.0456
C)0.3174
D)0.6826
E)0.9544

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Multiple Choice

Q 81Q 81

A design engineer wants to construct a sample mean chart for controlling the service life of a halogen headlamp his company produces. He knows from numerous previous samples that this service life is normally distributed with a mean of 500 hours and a standard deviation of 20 hours. On three recent production batches, he tested service life on random samples of four headlamps, with these results
If he uses upper and lower control limits of 520 and 480 hours, on what sample(s)(if any)does service life appear to be out of control?
A)sample 1
B)sample 2
C)sample 3
D)both samples 2 and 3
E)all samples are in control

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Multiple Choice

Q 82Q 82

A quality analyst wants to construct a sample mean chart for controlling a packaging process. He knows from past experience that whenever this process is in control, package weight is normally distributed with a mean of 20 ounces and a standard deviation of two ounces. Each day last week, he randomly selected four packages and weighed each
What is the sample mean package weight for Thursday?
A)19 ounces
B)20 ounces
C)20.6 ounces
D)21 ounces
E)23 ounces

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Multiple Choice

Q 83Q 83

A quality analyst wants to construct a sample mean chart for controlling a packaging process. He knows from past experience that whenever this process is in control, package weight is normally distributed with a mean of 20 ounces and a standard deviation of two ounces. Each day last week, he randomly selected four packages and weighed each
What is the mean of the sampling distribution of sample means when this process is in control?
A)18 ounces
B)19 ounces
C)20 ounces
D)21 ounces
E)22 ounces

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Multiple Choice

Q 84Q 84

A quality analyst wants to construct a sample mean chart for controlling a packaging process. He knows from past experience that whenever this process is in control, package weight is normally distributed with a mean of 20 ounces and a standard deviation of two ounces. Each day last week, he randomly selected four packages and weighed each
What is the standard deviation of the sampling distribution of sample means for whenever this process is in control?
A)0.1 ounces
B)0.4 ounces
C)0.5 ounces
D)1 ounce
E)2 ounces

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Multiple Choice

Q 85Q 85

A quality analyst wants to construct a sample mean chart for controlling a packaging process. He knows from past experience that whenever this process is in control, package weight is normally distributed with a mean of 20 ounces and a standard deviation of two ounces. Each day last week, he randomly selected four packages and weighed each
If he uses upper and lower control limits of 22 and 18 ounces, what is his risk (alpha)of concluding this process is out of control when it is actually in control (Type I error)?
A)0.0026
B)0.0456
C)0.3174
D)0.6826
E)0.9544

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Multiple Choice

Q 86Q 86

A quality analyst wants to construct a sample mean chart for controlling a packaging process. He knows from past experience that whenever this process is in control, package weight is normally distributed with a mean of 20 ounces and a standard deviation of two ounces. Each day last week, he randomly selected four packages and weighed each
If he uses upper and lower control limits of 22 and 18 ounces, on what day(s), if any, does this process appear to be out of control?
A)Monday
B)Tuesday
C)Monday and Tuesday
D)Monday, Tuesday, and Thursday
E)None

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Multiple Choice

Q 87Q 87

A quality analyst wants to construct a control chart for determining whether three machines, all producing the same product, are in control with regard to a particular quality variable. Accordingly, he sampled four units of output from each machine, with the following results
What is the sample mean for machine #1?
A)15
B)16
C)17
D)21
E)23

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Multiple Choice

Q 88Q 88

A quality analyst wants to construct a control chart for determining whether three machines, all producing the same product, are in control with regard to a particular quality variable. Accordingly, he sampled four units of output from each machine, with the following results
What is the estimate of the mean of the sampling distribution for the sample mean?
A)16
B)19
C)20
D)21
E)23

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Multiple Choice

Q 89Q 89

A quality analyst wants to construct a control chart for determining whether three machines, all producing the same product, are in control with regard to a particular quality variable. Accordingly, he sampled four units of output from each machine, with the following results
What is the estimate of the sample average range based upon this limited sample?
A)13.0
B)4.33
C)5.4
D)4.2
E)2.0

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Multiple Choice

Q 90Q 90

A quality analyst wants to construct a control chart for determining whether three machines, all producing the same product, are in control with regard to a particular quality variable. Accordingly, he sampled four units of output from each machine, with the following results
What are the x-bar chart three-sigma upper and lower control limits?
A)22 and 18
B)23.29 and 16.71
C)23.5 and 16.5
D)23.16 and 16.84
E)24 and 16

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Multiple Choice

Q 91Q 91

A quality analyst wants to construct a control chart for determining whether three machines, all producing the same product, are in control with regard to a particular quality variable. Accordingly, he sampled four units of output from each machine, with the following results
For upper and lower control limits of 23.29 and 16.71, which machine(s), if any, appear(s)to have an out-of-control process mean?
A)machine #1
B)machine #2
C)machine #3
D)all of the machines
E)none of the machines

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Multiple Choice

Q 92Q 92

The chair of the operations management department at Quality University wants to construct a p-chart for determining whether the four faculty teaching the basic P/OM course are in control with regard to the number of students who fail the course. Accordingly, he sampled 100 final grades from last year for each instructor, with the following results
What is the sample proportion of failures ( p)for Prof. D?
A)0
B).04
C).11
D).13
E).16

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Multiple Choice

Q 93Q 93

The chair of the operations management department at Quality University wants to construct a p-chart for determining whether the four faculty teaching the basic P/OM course are in control with regard to the number of students who fail the course. Accordingly, he sampled 100 final grades from last year for each instructor, with the following results
What is the estimate of the mean proportion of failures for these instructors?
A).10
B).11
C).13
D).16
E).40

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Multiple Choice

Q 94Q 94

The chair of the operations management department at Quality University wants to construct a p-chart for determining whether the four faculty teaching the basic P/OM course are in control with regard to the number of students who fail the course. Accordingly, he sampled 100 final grades from last year for each instructor, with the following results
What is the estimate of the standard deviation of the sampling distribution for an instructor's sample proportion of failures?
A).0075
B).03
C).075
D).3
E).75

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Multiple Choice

Q 95Q 95

The chair of the operations management department at Quality University wants to construct a p-chart for determining whether the four faculty teaching the basic P/OM course are in control with regard to the number of students who fail the course. Accordingly, he sampled 100 final grades from last year for each instructor, with the following results
What are the .95 (5 percent risk of Type I error)upper and lower control limits for the p-chart?
A).95 and .05
B).13 and .07
C).1588 and .0412
D).16 and .04
E).1774 and .0226

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Multiple Choice

Q 96Q 96

The chair of the operations management department at Quality University wants to construct a p-chart for determining whether the four faculty teaching the basic P/OM course are in control with regard to the number of students who fail the course. Accordingly, he sampled 100 final grades from last year for each instructor, with the following results
Using .95 control limits (5 percent risk of Type I error), which instructor(s), if any, should he conclude is (are)out of control?
A)none
B)Prof. B
C)Prof. D
D)both Prof. B and Prof. D
E)all

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Multiple Choice

Q 97Q 97

A quality analyst wants to construct a control chart for determining whether four machines, all producing the same product, are in control with regard to a particular quality attribute. Accordingly, she inspected 1,000 units of output from each machine in random samples, with the following results
What is the sample proportion of defectives for machine #1?
A).023
B).02
C).0115
D).0058
E).005

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Multiple Choice

Q 98Q 98

A quality analyst wants to construct a control chart for determining whether four machines, all producing the same product, are in control with regard to a particular quality attribute. Accordingly, she inspected 1,000 units of output from each machine in random samples, with the following results
What is the estimate of the process proportion of defectives?
A).08
B).06
C).04
D).02
E).01

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Multiple Choice

Q 99Q 99

A quality analyst wants to construct a control chart for determining whether four machines, all producing the same product, are in control with regard to a particular quality attribute. Accordingly, she inspected 1,000 units of output from each machine in random samples, with the following results
What is the estimate of the standard deviation of the sampling distribution of sample proportions for this process?
A).016
B).00016
C).04
D).0044
E).00002

Free

Multiple Choice

Q 100Q 100

A quality analyst wants to construct a control chart for determining whether four machines, all producing the same product, are in control with regard to a particular quality attribute. Accordingly, she inspected 1,000 units of output from each machine in random samples, with the following results
What are the control chart upper and lower control limits for an alpha risk of .05?
A).0272 and .0128
B).0287 and .0113
C).029 and .013
D).0303 and .0097
E).0332 and .0068

Free

Multiple Choice

Q 101Q 101

A quality analyst wants to construct a control chart for determining whether four machines, all producing the same product, are in control with regard to a particular quality attribute. Accordingly, she inspected 1,000 units of output from each machine in random samples, with the following results
For upper and lower control limits of .026 and .014, which machine(s), if any, appear(s)to be out-of-control for process proportion of defectives?
A)machine #3
B)machine #4
C)machines #3 and #4
D)machines #2 and #3
E)none of the machines

Free

Multiple Choice

Q 102Q 102

Studies on a bottle-filling machine indicate that it fills bottles to a mean of 16 ounces with a standard deviation of 0.10 ounces. What is the process specification, assuming the C

_{pk}index of 1? A)lower spec = 0.1 ounces and upper spec = 1 ounce B)lower spec = 14.3 ounces and upper spec = 17.7 ounces C)lower spec = 12.0 ounces and upper spec = 21.4 ounces D)lower spec = 15.7 ounces and upper spec = 16.3 ounces E)There is insufficient information to determine the process specification.Free

Multiple Choice

Q 103Q 103

Studies on a machine that molds plastic water pipe indicate that when it is injecting 1-inch-diameter pipe, the process standard deviation is 0.05 inches. The 1-inch pipe has a specification of 1 inch plus or minus 0.10 inch. What is the process capability index ( C

_{pk})if the long-run process mean is 1 inch? A)0.50 B)0.67 C)1.00 D)2.00 E)2.20Free

Multiple Choice

Q 104Q 104

The specification limits for a product are 8 cm and 10 cm. A process that produces the product has a mean of 9.5 cm and a standard deviation of 0.2 cm. What is the process capability, C

_{pk}? A)3.33 B)1.67 C)0.83 D)2.50 E)1.33Free

Multiple Choice

Q 105Q 105

The specifications for a product are 6 mm ± 0.1 mm. The process is known to operate at a mean of 6.05 with a standard deviation of 0.01 mm. What is the C

_{pk}for this process? A)3.33 B)1.67 C)5.00 D)2.50 E)1.33Free

Multiple Choice

Q 106Q 106

Organizations should work to improve process capability so thatinspection efforts can become more
A)effective.
B)efficient.
C)necessary.
D)unnecessary.
E)widespread.

Free

Multiple Choice

Q 107Q 107

A process results in a few defects occurring in each unit of output. Long-run, these defects should be monitored with
A)p-charts.
B)c-charts.
C)x-bar charts.
D)R-charts.
E)o-charts.

Free

Multiple Choice

Q 108Q 108

When a process is in control, it results in there being, on average, 16 defects per unit of output. c-chart limits of 8 and 24 would lead to a _____ percent chance of a Type I error.
A)68.26
B)95.44
C)31.74
D)0.26
E)4.56

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Multiple Choice

Q 109Q 109

When a process is in control, it results in there being, on average, 16 defects per unit of output. chart limits of 4 and 28 would lead to a _____ percent chance of a Type I error.
A)68.26
B)95.44
C)31.74
D)0.26
E)4.56

Free

Multiple Choice

Q 110Q 110

The basis for a statistical process control chart is a(the)
A)process capability.
B)sampling distribution.
C)control limit.
D)sample range.
E)sample mean.

Free

Multiple Choice

Q 111Q 111

The approaches to quality assurance are
A)process inspection, control analysis, and continuous improvement.
B)identification, analysis, and quality assurance
C)analysis, quality assurance, and modifications.
D)inspection alone, process control, and continuous improvement.
E)quality identification, process correction, and improvement inspection

Free

Multiple Choice

Q 112Q 112

The basic issues of inspection include all of the following except
A)how much to inspect and how often
B)whether to inspect in a centralized or on-site location
C)at what points in the process inspection should occur
D)whether to inspect attributes or variables
E)what will be the total cost involved

Free

Multiple Choice

Q 113Q 113

This step in the control process includes characteristics that can be counted.
A)define
B)compare
C)measure
D)evaluate
E)correct

Free

Multiple Choice

Q 114Q 114

This step in the control process includes sufficient detail about what is to be controlled.
A)define
B)compare
C)measure
D)evaluate
E)correct

Free

Multiple Choice

Q 115Q 115

This step in the control process includes a standard that can be used to evaluate the measurements.
A)define
B)compare
C)measure
D)evaluate
E)correct

Free

Multiple Choice

Q 116Q 116

This step in the control process includes a definition of out of control.
A)define
B)compare
C)measure
D)evaluate
E)correct

Free

Multiple Choice

Q 117Q 117

This step in the control process includes adjustments when a process is found to be out of control.
A)define
B)compare
C)measure
D)evaluate
E)correct

Free

Multiple Choice