Question 1

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.

Accepted Answer

The answer of Consider the following information

The number of runs...

Question 2

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 III

Accepted Answer

The process capability index can indeed be misleading if the process is not stable, the process output is not normally distributed, or the process is not centered. Stability is crucial for the index to reflect true capability, normal distribution is often assumed in the calculation of capability indices, and centering affects the calculation of indices like Cp and Cpk, which measure how well a process can produce output within specification limits.

Question 3

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.

Accepted Answer

Control charts are used to monitor process variation and help identify whether variations are due to common causes (random variation) or special causes (assignable variation).

Question 4

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

Accepted Answer

The answer of If a process is performing as it...

Question 5

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.

Accepted Answer

The answer of Consider the following information

The number of runs...

Question 6

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

Accepted Answer

The answer of Which of the following relationships must always...

Question 7

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

Accepted Answer

The answer of A design engineer wants to construct a...

Question 8

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.

Accepted Answer

An x-bar chart is specifically designed to monitor the process mean over time and is therefore the most effective tool for detecting shifts in the process mean for a measured characteristic.

Question 9

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

Accepted Answer

The answer of A design engineer wants to construct a...

Question 10

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

Accepted Answer

A time-ordered plot of sample statistics is called a control chart. Control charts are used in quality control to monitor processes over time and identify any variations or trends.

Question 11

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.

Accepted Answer

100 percent inspection is not typically considered a step in the control process. The control process generally involves defining what needs to be controlled, comparing actual performance against standards, taking corrective action if necessary, and evaluating the effectiveness of the corrective action. 100 percent inspection is more related to quality control methods and is not a fundamental step in the general control process framework.

Question 12

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

Accepted Answer

The probability of concluding that assignable variation exists when only random variation is present is the probability of a Type I error (I) and is known as the alpha risk (II). It is also represented by the sum of probabilities in the two tails of the normal distribution (IV), which are the critical regions for rejecting the null hypothesis when it is actually true.

Question 13

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

Accepted Answer

A plot below the lower control limit on the range chart indicates a decrease in process variation, which could be due to an assignable cause. It's not something to be ignored as it might signify an improvement or an issue that needs to be understood and possibly standardized.

Question 14

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.

Accepted Answer

An R-chart is used to monitor the variability of a process. A point outside the lower control limit suggests an unusual or non-random variation, indicating that an assignable cause of variation might be present and should be investigated.

Question 15

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.

Accepted Answer

The range chart (R-chart) is designed to monitor the variability or dispersion within a process. It detects shifts or changes in the distribution's spread, not its central tendency or proportion.

Question 16

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

Accepted Answer

The answer of A design engineer wants to construct a...

Question 17

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.

Accepted Answer

The answer of The following data occurs chronologically from left...

Question 18

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

Accepted Answer

Assignable variation is the type of variation whose cause can be identified and potentially eliminated. It is distinct from random variation, which is inherent to the process and cannot be easily traced to a specific cause.

Question 19

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

Accepted Answer

The answer of A design engineer wants to construct a...

Question 20

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.

Accepted Answer

The optimum level of inspection is achieved when the total cost, which includes both the cost of inspection and the cost of passing defectives, is at its minimum. This balance ensures efficiency and quality control.

Quiz 10: Quality Control

Consider the following information The number of runs up and down for the preceding data is

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.

The purpose of control charts is to

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

Consider the following information The number of runs above and below the sample median is:

Which of the following relationships must always be incorrect?

A shift in the process mean for a measured characteristic would most likely be detected by a

A time-ordered plot of sample statistics is called a(n) _____ chart.

Which of the following is not a step in the control process?

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 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 point which is outside of the lower control limit on an R-chart

The range chart ( R-chart) is most likely to detect a change in

The following data occurs chronologically from left to right The number of runs up and down is:

_____ variation is a variation whose cause can be identified.

The traditional view is that the optimum level of inspection is where the

Quiz 10: Quality Control

Consider the following information The number of runs up and down for the preceding data is

The process capability index (Cpk) may mislead if (I) the process is not stable.(II) the process output is not normally distributed.(III) the process is not centered.

The purpose of control charts is to

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

Consider the following information The number of runs above and below the sample median is:

Which of the following relationships must always be incorrect?

A shift in the process mean for a measured characteristic would most likely be detected by a

A time-ordered plot of sample statistics is called a(n) _____ chart.

Which of the following is not a step in the control process?

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 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 point which is outside of the lower control limit on an R-chart

The range chart ( R-chart) is most likely to detect a change in

The following data occurs chronologically from left to right The number of runs up and down is:

_____ variation is a variation whose cause can be identified.

The traditional view is that the optimum level of inspection is where the

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.