Question 1

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.

Accepted Answer

A)   I and II
B)   I and IV
C)   II and III
D)   I, II, and IV
E)   I, III, and IVF) B) and C)
G) C) and D)

Question 2

A control chart used to monitor the fraction of defectives generated by a process is the:

Accepted Answer

A)   p-chart.
B)   R-chart.
C)   x-bar chart.
D)   c-chart.
E)   Gantt chart.F) B) and D)
G) D) and E)

Question 3

A control chart used to monitor the process mean is the:

Accepted Answer

A)   p-chart.
B)   R-chart.
C)   x-bar chart.
D)   c-chart.
E)   Gantt chart.F) D) and E)
G) A) and B)

Question 4

The best way to assure quality is to use extensive inspection and control charts.

Accepted Answer

A) True 
 B)False

Question 5

A run test checks a sequence of observations for randomness.

Accepted Answer

A) True 
 B)False

Question 6

Larger samples will require wider x-bar control limits because there is more data.

Accepted Answer

A) True 
 B)False

Question 7

Patterns of data on a control chart suggest that the process may have nonrandom variation.

Accepted Answer

A) True 
 B)False

Question 8

Range charts are used mainly with attribute data.

Accepted Answer

A) True 
 B)False

Question 9

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 (Cpk)  if the long-run process mean is 1 inch?

Accepted Answer

A)   0.50
B)   0.67
C)   1.00
D)   2.00
E)   2.20F) D) and E)
G) A) and E)

Question 10

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:   Instructor  Number of Failures  Prof. A 13 Prof. B 0 Prof. C 11 Prof. D 16\begin{array} { l c } 	ext { Instructor } & 	ext { Number of Failures } \\hline 	ext { Prof. A } & 13 \	ext { Prof. B } & 0 \	ext { Prof. C } & 11 \	ext { Prof. D } & 16\end{array} Instructor  Prof. A  Prof. B  Prof. C  Prof. D ​ Number of Failures 1301116​​ 
Using .95 control limits (5 percent risk of Type I error) , which instructor(s) , if any, should he conclude is (are)  out of control?

Accepted Answer

A)   none
B)   Prof. B
C)   Prof. D
D)   both Prof. B and Prof. D
E)   all F) A) and B)
G) A) and C)

Question 11

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.

Accepted Answer

A) True 
 B)False

Question 12

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

Accepted Answer

A) True 
 B)False

Question 13

The amount of inspection needed depends on __________ and __________.

Accepted Answer

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 inspectedF) All of the above
G) A) and D)

Question 14

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:   Sample  Service Life (hours)  149550050550025255155055153470480460470\begin{array} { c c c c c } 	ext { Sample } && { 	ext { Service Life (hours)  } } \\hline 1 & 495 & 500 & 505 & 500 \2 & 525 & 515 & 505 & 515 \3 & 470 & 480 & 460 & 470\end{array} Sample 123​495525470​ Service Life (hours)  500515480​505505460​500515470​​ 
What is the standard deviation of the sampling distribution of sample means for whenever service life is in control?

Accepted Answer

A)   5 hours
B)   6.67 hours
C)   10 hours
D)   11.55 hours
E)   20 hours F) A) and E)
G) All of the above

Question 15

Attribute data are counted, variable data are measured.

Accepted Answer

A) True 
 B)False

Question 16

Which of the following quality control sample statistics indicates a quality characteristic that is an attribute?

Accepted Answer

A)   mean
B)   variance
C)   standard deviation
D)   range
E)   proportionF) C) and D)
G) B) and C)

Question 17

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:   Machine  Total Defectives #123#215#329#413\begin{array} { c c } 	ext { Machine } & 	ext { Total Defectives } \\hline \# 1 & 23 \\# 2 & 15 \\# 3 & 29 \\# 4 & 13\end{array} Machine #1#2#3#4​ Total Defectives 23152913​​ 
What is the sample proportion of defectives for machine #1?

Accepted Answer

A)   .023
B)   .02
C)   .0115
D)   .0058
E)   .005 F) B) and D)
G) All of the above

Question 18

Which of the following relationships must always be incorrect?

Accepted Answer

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

F) A) and D)
G) B) and D)

Correct Answer
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Question 19

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, Cpk?

Accepted Answer

A)   3.33
B)   1.67
C)   0.83
D)   2.50
E)   1.33F) B) and D)
G) B) and C)

Question 20

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:   Machine  Total Defectives #123#215#329#413\begin{array} { c c } 	ext { Machine } & 	ext { Total Defectives } \\hline \# 1 & 23 \\# 2 & 15 \\# 3 & 29 \\# 4 & 13\end{array} Machine #1#2#3#4​ Total Defectives 23152913​​ 
What is the estimate of the standard deviation of the sampling distribution of sample proportions for this process?

Accepted Answer

A)   .016
B)   .00016
C)   .04
D)   .0044
E)   .00002 F) B) and E)
G) A) and B)

Exam 14: Quality Control

Which of the following quality control sample statistics indicates a quality characteristic that is an attribute?

Correct Answer
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Range charts are used mainly with attribute data.

Correct Answer
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Correct Answer
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Larger samples will require wider x-bar control limits because there is more data.

Correct Answer
verified

A control chart used to monitor the process mean is the:

Correct Answer
verified

Correct Answer
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A control chart used to monitor the fraction of defectives generated by a process is the:

Correct Answer
verified

The amount of inspection needed depends on and .

Correct Answer
verified

Patterns of data on a control chart suggest that the process may have nonrandom variation.

Correct Answer
verified

Which of the following relationships must always be incorrect?

Correct Answer
verified

Correct Answer
verified

The best way to assure quality is to use extensive inspection and control charts.

Correct Answer
verified

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.

Correct Answer
verified

Correct Answer
verified

A run test checks a sequence of observations for randomness.

Correct Answer
verified

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.

Correct Answer
verified

Correct Answer
verified

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, Cpk?

Correct Answer
verified

Attribute data are counted, variable data are measured.

Correct Answer
verified

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

Correct Answer
verified

Exam 14: Quality Control

Which of the following quality control sample statistics indicates a quality characteristic that is an attribute?

Correct AnswerverifiedShow Answer

Range charts are used mainly with attribute data.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Larger samples will require wider x-bar control limits because there is more data.

Correct AnswerverifiedShow Answer

A control chart used to monitor the process mean is the:

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

A control chart used to monitor the fraction of defectives generated by a process is the:

Correct AnswerverifiedShow Answer

The amount of inspection needed depends on __________ and __________.

Correct AnswerverifiedShow Answer

Patterns of data on a control chart suggest that the process may have nonrandom variation.

Correct AnswerverifiedShow Answer

Which of the following relationships must always be incorrect?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

The best way to assure quality is to use extensive inspection and control charts.

Correct AnswerverifiedShow Answer

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.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

A run test checks a sequence of observations for randomness.

Correct AnswerverifiedShow Answer

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.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

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, Cpk?

Correct AnswerverifiedShow Answer

Attribute data are counted, variable data are measured.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Correct Answer
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The amount of inspection needed depends on and .

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