Question 1

The acceptable quality level (AQL)is the average level of quality we are willing to accept.

Accepted Answer

A) True 
 B)False

Question 2

If the Cpk index exceeds 1:

Accepted Answer

A) the AQL must be smaller than the LTPD. 
B) σ must be less than one-third of the absolute value of the difference between each specification limit and the process mean. 
C) the x-bar chart must indicate that the process is in control. 
D) the process is capable of Six Sigma quality. 
E) the process is characterized as "not capable." 
A) the AQL must be smaller than the LTPD. 
B) σ must be less than one-third of the absolute value of the difference between each specification limit and the process mean. 
C) the x-bar chart must indicate that the process is in control. 
D) the process is capable of Six Sigma quality. 
E) the process is characterized as "not capable."

Question 3

Which of the following statements about acceptance sampling is true?

Accepted Answer

A) Acceptance sampling draws a sample from a population of items,tests the sample,accepts the entire population if the sample is good enough,and rejects it if the sample is poor enough. 
B) The sampling plan contains information about the sample size to be drawn and the critical acceptance or rejection numbers for that sample size. 
C) The steeper an operating characteristic curve,the better its ability to discriminate between good and bad lots. 
D) All of the above are true. 
E) All of the above are false. 
A) Acceptance sampling draws a sample from a population of items,tests the sample,accepts the entire population if the sample is good enough,and rejects it if the sample is poor enough. 
B) The sampling plan contains information about the sample size to be drawn and the critical acceptance or rejection numbers for that sample size. 
C) The steeper an operating characteristic curve,the better its ability to discriminate between good and bad lots. 
D) All of the above are true. 
E) All of the above are false.

Question 4

Which of the following is true regarding the process capability index Cpk?

Accepted Answer

A) A Cpk index value of 1 is the highest possible. 
B) The larger the Cpk,the more units meet specifications. 
C) The Cpk index can only be used when the process centerline is also the specification centerline. 
D) Positive values of the Cpk index are good; negative values are bad. 
E) Its value will always be at least as large as the Cp value for the same process. 
A) A Cpk index value of 1 is the highest possible. 
B) The larger the Cpk,the more units meet specifications. 
C) The Cpk index can only be used when the process centerline is also the specification centerline. 
D) Positive values of the Cpk index are good; negative values are bad. 
E) Its value will always be at least as large as the Cp value for the same process.

Question 5

To set x-bar chart upper and lower control limits,one must know the process central line,which is the:

Accepted Answer

A) average of the sample means. 
B) total number of defects in the population. 
C) percent defects in the population. 
D) size of the population. 
E) average range. 
A) average of the sample means. 
B) total number of defects in the population. 
C) percent defects in the population. 
D) size of the population. 
E) average range.

Question 6

If a process has only natural variations,________ percent of the time the sample averages will fall inside the ±3-sigma control limits.

Accepted Answer

The answer of If a process has only natural variations,________...

Question 7

A manager wishes to build a 3-sigma range chart for a process.The sample size is five,the mean of sample means is 16.01,and the average range is 5.3.From Table S6.1,the appropriate value of D3 is 0,and D4 is 2.115.What are the UCL and LCL,respectively,for this range chart?

Accepted Answer

A) 33.9 and 11.2 
B) 33.9 and 0 
C) 11.2 and 0 
D) 6.3 and 0 
E) 31.91 and 0.11 
A) 33.9 and 11.2 
B) 33.9 and 0 
C) 11.2 and 0 
D) 6.3 and 0 
E) 31.91 and 0.11

Question 8

A c-chart is appropriate to plot the number of flaws in a bolt of fabric.

Accepted Answer

A) True 
 B)False

Question 9

A process range chart illustrates the amount of dispersion within the samples.

Accepted Answer

A) True 
 B)False

Question 10

The causes of variation in statistical process control are:

Accepted Answer

A) cycles,trends,seasonality,and random variations. 
B) producer's causes and consumer's causes. 
C) mean and range. 
D) natural causes and assignable causes. 
E) Type I and Type II. 
A) cycles,trends,seasonality,and random variations. 
B) producer's causes and consumer's causes. 
C) mean and range. 
D) natural causes and assignable causes. 
E) Type I and Type II.

Question 11

A quality analyst wants to construct a sample mean chart for controlling a packaging process.He knows from past experience that when the process is operating as intended,packaging weight is normally distributed with a mean of twenty ounces,and a process standard deviation of two ounces.Each day last week,he randomly selected four packages and weighed each.The data from that activity appear below.
   (a)If he sets an upper control limit of 21 and a lower control limit of 19 around the target value of twenty ounces,the control chart is based on what value of z?
(b)With the UCL and LCL of part a,what do you conclude about this process-is it in control?

Accepted Answer

(a)These control limits are one standard

Question 12

Pierre's Motorized Pirogues and Mudboats is setting up an acceptance sampling plan for the special air cleaners he manufactures for his boats.His specifications,and the resulting plan,are shown on the POM for Windows output below.Pierre is a bit confused.He mistakenly thinks that acceptance sampling will reject all bad lots and accept all good lots.Explain why this will not happen.

Accepted Answer

Acceptance sampling cannot discriminate

Question 13

A process that is in statistical control will always yield products that meet their design specifications.

Accepted Answer

A) True 
 B)False

Question 14

Mistakes stemming from workers' inadequate training represent an assignable cause of variation.

Accepted Answer

A) True 
 B)False

Question 15

Cartons of Plaster of Paris are supposed to weigh exactly 32 oz.Inspectors want to develop process control charts.They take ten samples of six boxes each and weigh them.Based on the following data,compute the lower and upper control limits and determine whether the process is in control.

Accepted Answer

n = 6; overall mean = 34.23; @#IMG-DLM& = 0.52. @#IMG-DLM& @#IMG-DLM&

Question 16

Statistical process control charts:

Accepted Answer

A) display the measurements on every item being produced. 
B) display upper and lower limits for process variables or attributes and signal when a process is no longer in control. 
C) indicate to the process operator the average outgoing quality of each lot. 
D) indicate to the operator the true quality of material leaving the process. 
E) are a graphic way of classifying problems by their level of importance,often referred to as the 80-20 rule. 
A) display the measurements on every item being produced. 
B) display upper and lower limits for process variables or attributes and signal when a process is no longer in control. 
C) indicate to the process operator the average outgoing quality of each lot. 
D) indicate to the operator the true quality of material leaving the process. 
E) are a graphic way of classifying problems by their level of importance,often referred to as the 80-20 rule.

Question 17

The term ________ is used to describe how well a process makes units within design specifications (or tolerances).

Accepted Answer

The answer of The term ________ is used to describe...

Question 18

What do the terms producer's risk and consumer's risk mean?

Accepted Answer

Producer's risk: the risk of r

Question 19

A city police chief decides to do an annual review of the police department by checking the number of monthly complaints.If the total number of complaints in each of the 12 months were 15,18,13,12,16,20,5,10,9,11,8,and 3 and the police chief wants a 90% confidence level,are the complaints in control?

Accepted Answer

From Table S6.2 z = 1.65 c-bar = (15 + 1

Question 20

The defect rate for a product has historically been about 1.6%.What are the upper and lower control chart limits for a p-chart,if you wish to use a sample size of 100 and 3-sigma limits?

Accepted Answer

UCLp = @#IMG-DLM& + 3 @#IMG-DLM& = 0.016

Exam 20: Statistical Process Control

The acceptable quality level (AQL)is the average level of quality we are willing to accept.

If the Cpk index exceeds 1:

Which of the following statements about acceptance sampling is true?

Which of the following is true regarding the process capability index Cpk?

To set x-bar chart upper and lower control limits,one must know the process central line,which is the:

If a process has only natural variations,________ percent of the time the sample averages will fall inside the ±3-sigma control limits.

A manager wishes to build a 3-sigma range chart for a process.The sample size is five,the mean of sample means is 16.01,and the average range is 5.3.From Table S6.1,the appropriate value of D3 is 0,and D4 is 2.115.What are the UCL and LCL,respectively,for this range chart?

A c-chart is appropriate to plot the number of flaws in a bolt of fabric.

A process range chart illustrates the amount of dispersion within the samples.

The causes of variation in statistical process control are:

A process that is in statistical control will always yield products that meet their design specifications.

Mistakes stemming from workers' inadequate training represent an assignable cause of variation.

Cartons of Plaster of Paris are supposed to weigh exactly 32 oz.Inspectors want to develop process control charts.They take ten samples of six boxes each and weigh them.Based on the following data,compute the lower and upper control limits and determine whether the process is in control.

Statistical process control charts:

The term ________ is used to describe how well a process makes units within design specifications (or tolerances).

What do the terms producer's risk and consumer's risk mean?

The defect rate for a product has historically been about 1.6%.What are the upper and lower control chart limits for a p-chart,if you wish to use a sample size of 100 and 3-sigma limits?

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