Question 1

For which of the following should we use an R-chart to monitor process quality?

Accepted Answer

A) Weighing trucks at a highway inspection station to determine if they are overloaded 
B) Deciding whether an airliner has sufficient fuel for its trip 
C) Student grades measured from 1 to 100 
D) Determining whether vehicles from a motor pool will run 
E) Determining the accuracy of a forecast of "snow" 
A) Weighing trucks at a highway inspection station to determine if they are overloaded 
B) Deciding whether an airliner has sufficient fuel for its trip 
C) Student grades measured from 1 to 100 
D) Determining whether vehicles from a motor pool will run 
E) Determining the accuracy of a forecast of "snow"

Question 2

In monitoring process quality, we might use which of the following statistics?

Accepted Answer

A) Absolute values 
B) Percentage deviation from tolerance centers 
C) "k" values for the sample mean 
D) Logarithmic control intervals 
E) Difference between the highest and lowest value in a sample 
A) Absolute values 
B) Percentage deviation from tolerance centers 
C) "k" values for the sample mean 
D) Logarithmic control intervals 
E) Difference between the highest and lowest value in a sample

Question 3

You want to determine the control lines for a p-chart for quality control purposes.If the total number of defects from all samples is 560, the number of samples is 70, and the sample size is 80, which of the following would be the standard deviation used in developing the control lines?

Accepted Answer

A) 0.9000 
B) 0.4556 
C) 0.0335 
D) 0.0011 
E) 0.0112 
A) 0.9000 
B) 0.4556 
C) 0.0335 
D) 0.0011 
E) 0.0112

Question 4

If the fraction defective is 0.4 based on a sample size of 100, the standard deviation used in the p-chart is about 0.10.

Accepted Answer

A) True 
 B)False

Question 5

Total, 100 percent inspection can never be cost justified.

Accepted Answer

A) True 
 B)False

Question 6

Variation in production systems that is caused by factors that can be clearly identified and possibly even managed is called assignable variation.

Accepted Answer

A) True 
 B)False

Question 7

You have just used the capability index (Cpk) formulas to compute the two values "min [2, 2.5]." Which of the following is the proper interpretation of these numbers?

Accepted Answer

A) The true capability index value is 2.5. 
B) The mean of the production process has shifted to the left of the design limits. 
C) The mean of the production process has shifted to the right of the design limits. 
D) The mean has not shifted at all. 
E) The true capability index value is between 2 and 2.5. 
A) The true capability index value is 2.5. 
B) The mean of the production process has shifted to the left of the design limits. 
C) The mean of the production process has shifted to the right of the design limits. 
D) The mean has not shifted at all. 
E) The true capability index value is between 2 and 2.5.

Question 8

You want to determine the control lines for a p-chart for quality control purposes.If the total number of defects from all samples is 560, the number of samples is 70, and the sample size is 80, what would be the standard deviation used in developing the control lines? ______________________________________

Accepted Answer

0.0335
Explanation: From Equation 13.4,

Question 9

To obtain a 99.7 percent confidence level in a p-chart, we would use a value of 3 for "z".

Accepted Answer

A) True 
 B)False

Question 10

You want to determine the control lines for a p-chart for quality control purposes.If the total number of defects from all samples is 2,500, the number of samples is 100, and the sample size is 50, which of the following would be the standard deviation used in developing the control lines?

Accepted Answer

A) 0.4900 
B) 0.2499 
C) 0.1556 
D) 0.0707 
E) 0.02499 
A) 0.4900 
B) 0.2499 
C) 0.1556 
D) 0.0707 
E) 0.02499

Question 11

An example of assignable variation in a production system may be that workers are not identically trained.

Accepted Answer

A) True 
 B)False

Question 12

A p-chart has upper and lower control limits expressed as lines on the chart.As long as the sample values fall between these two lines, there is no need to investigate process behavior.

Accepted Answer

A) True 
 B)False

Question 13

An example of assignable variation in a production system may be that a machine is not adjusted properly.

Accepted Answer

A) True 
 B)False

Question 14

For which of the following should we use an R-chart to monitor process quality?

Accepted Answer

A) Grades in a freshman "pass/fail" course 
B) Tire pressures in an auto assembly plant 
C) Vehicles passing emissions inspection 
D) Computer software errors 
E) Number of units with missing operations 
A) Grades in a freshman "pass/fail" course 
B) Tire pressures in an auto assembly plant 
C) Vehicles passing emissions inspection 
D) Computer software errors 
E) Number of units with missing operations

Question 15

Sampling plans are generally displayed graphically through the use of operating characteristic (OC) curves.

Accepted Answer

A) True 
 B)False

Question 16

You want to develop a three-sigma R-chart.You know the average range is 5 based on several samples of size 10.Which of the following is the resulting UCL? _______________________________________

Accepted Answer

8.9
Explanation: Fro

Question 17

Acceptance sampling is performed on goods that already exist to determine what percentage of items conforms to specifications.

Accepted Answer

A) True 
 B)False

Question 18

If the fraction defective is 0.12 based on a sample size of 16, the standard deviation used in the p-chart is about 0.08.

Accepted Answer

A) True 
 B)False

Question 19

The capability index (Cpk) indicates the position of the mean and tails of a process's variance relative to design specifications.

Accepted Answer

A) True 
 B)False

Question 20

The capability index is used to gauge economic changes in service systems.

Accepted Answer

A) True 
 B)False

Exam 13: Statistical Quality Control

For which of the following should we use an R-chart to monitor process quality?

In monitoring process quality, we might use which of the following statistics?

You want to determine the control lines for a p-chart for quality control purposes.If the total number of defects from all samples is 560, the number of samples is 70, and the sample size is 80, which of the following would be the standard deviation used in developing the control lines?

If the fraction defective is 0.4 based on a sample size of 100, the standard deviation used in the p-chart is about 0.10.

Total, 100 percent inspection can never be cost justified.

Variation in production systems that is caused by factors that can be clearly identified and possibly even managed is called assignable variation.

You have just used the capability index (Cpk) formulas to compute the two values "min [2, 2.5]." Which of the following is the proper interpretation of these numbers?

To obtain a 99.7 percent confidence level in a p-chart, we would use a value of 3 for "z".

You want to determine the control lines for a p-chart for quality control purposes.If the total number of defects from all samples is 2,500, the number of samples is 100, and the sample size is 50, which of the following would be the standard deviation used in developing the control lines?

An example of assignable variation in a production system may be that workers are not identically trained.

A p-chart has upper and lower control limits expressed as lines on the chart.As long as the sample values fall between these two lines, there is no need to investigate process behavior.

An example of assignable variation in a production system may be that a machine is not adjusted properly.

For which of the following should we use an R-chart to monitor process quality?

Sampling plans are generally displayed graphically through the use of operating characteristic (OC) curves.

You want to develop a three-sigma R-chart.You know the average range is 5 based on several samples of size 10.Which of the following is the resulting UCL? _______________________________________

Acceptance sampling is performed on goods that already exist to determine what percentage of items conforms to specifications.

If the fraction defective is 0.12 based on a sample size of 16, the standard deviation used in the p-chart is about 0.08.

The capability index (Cpk) indicates the position of the mean and tails of a process's variance relative to design specifications.

The capability index is used to gauge economic changes in service systems.

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