Question 1

An x-bar chart is used when we are sampling attributes.

Accepted Answer

A) True 
 B)False

Question 2

Which of the following is true of a p-chart?

Accepted Answer

A) The lower control limit is found by subtracting a fraction from the average number of defects. 
B) The lower control limit indicates the minimum acceptable number of defects. 
C) The lower control limit equals D3 times p-bar. 
D) The lower control limit may be at zero. 
E) The lower control limit is the same as the lot tolerance percent defective. 
A) The lower control limit is found by subtracting a fraction from the average number of defects. 
B) The lower control limit indicates the minimum acceptable number of defects. 
C) The lower control limit equals D3 times p-bar. 
D) The lower control limit may be at zero. 
E) The lower control limit is the same as the lot tolerance percent defective.

Question 3

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 wants acceptance sampling to remove ALL defects from his production of air cleaners.Explain carefully why this won't happen.

Accepted Answer

Acceptance sampling is not intended to r

Question 4

What is the statistical process chart used to control the number of defects per unit of output?

Accepted Answer

A) x-bar chart 
B) R-chart 
C) p-chart 
D) AOQ chart 
E) c-chart 
A) x-bar chart 
B) R-chart 
C) p-chart 
D) AOQ chart 
E) c-chart

Question 5

According to the text,what is the most common choice of limits for control charts?

Accepted Answer

A) ±1 standard deviation 
B) ±2 standard deviations 
C) ±3 standard deviations 
D) ±3 standard deviations for means and ± 2 standard deviations for ranges 
E) ±6 standard deviations 
A) ±1 standard deviation 
B) ±2 standard deviations 
C) ±3 standard deviations 
D) ±3 standard deviations for means and ± 2 standard deviations for ranges 
E) ±6 standard deviations

Question 6

A manufacturer uses statistical process control to control the quality of the firm's products.Samples of 50 of Product A are taken,and a defective/acceptable decision is made on each unit sampled.For Product B,the number of flaws per unit is counted.What type(s)of control charts should be used?

Accepted Answer

A) p-charts for both A and B 
B) p-chart for A,c-chart for B 
C) c-charts for both A and B 
D) p-chart for A,mean and range charts for B 
E) c-chart for A,mean and range charts for B 
A) p-charts for both A and B 
B) p-chart for A,c-chart for B 
C) c-charts for both A and B 
D) p-chart for A,mean and range charts for B 
E) c-chart for A,mean and range charts for B

Question 7

Mean charts and range charts complement one another,one detecting shifts in process average,the other detecting shifts in process dispersion.

Accepted Answer

A) True 
 B)False

Question 8

If a sample of items is taken and the mean of the sample is outside the control limits,the process is:

Accepted Answer

A) likely out of control and the cause should be investigated. 
B) in control,but not capable of producing within the established control limits. 
C) within the established control limits with only natural causes of variation. 
D) monitored closely to see if the next sample mean will also fall outside the control limits. 
E) producing high quality products. 
A) likely out of control and the cause should be investigated. 
B) in control,but not capable of producing within the established control limits. 
C) within the established control limits with only natural causes of variation. 
D) monitored closely to see if the next sample mean will also fall outside the control limits. 
E) producing high quality products.

Question 9

What are the three possible results (or findings)from the use of control charts?

Accepted Answer

The results of a control chart

Question 10

Ten samples of size four were taken from a process,and their weights measured.The sample averages and sample ranges are in the following table.Construct and plot an x-bar and R-chart using these data.Is the process in control?

Accepted Answer

@#IMG-DLM& @#IMG-DLM& The x-bar chart is out of co

Question 11

The width of a bronze bar is intended to be one-eighth of an inch (0.125 inches).Inspection samples contain five bars each.The average range of these samples is 0.01 inches.What are the upper and lower control limits for the x-bar and R-chart for this process,using 3-sigma limits?

Accepted Answer

x-bar chart: LCL = .

Question 12

Acceptance sampling is usually used to control:

Accepted Answer

A) the number of units of output from one stage of a process that are then sent to the next stage. 
B) the number of units delivered to the customer. 
C) the quality of work-in-process inventory. 
D) incoming lots of purchased products. 
E) all of the above. 
A) the number of units of output from one stage of a process that are then sent to the next stage. 
B) the number of units delivered to the customer. 
C) the quality of work-in-process inventory. 
D) incoming lots of purchased products. 
E) all of the above.

Question 13

A woodworker is concerned about the quality of the finished appearance of her work.In sampling units of a split-willow hand-woven basket,she has found the following number of finish defects in ten units sampled: 4,0,3,1,2,0,1,2,0,2.
a.Calculate the average number of defects per basket.
b.If 3-sigma control limits are used,calculate the lower control limit and upper control limit.

Accepted Answer

(a)1.5; (b

Question 14

Examine the Statistical Process Control outputs below.Answer the following questions.
a.What is the sample size?
b.What is the number of samples?
c.What is the mean of sample 8; what is the range of sample 10?
d..Is this process in control? Explain--a simple Yes or No is insufficient.
e.What additional steps should the quality assurance team take?

Accepted Answer

a.The sample size is 4.b.ten samples wer

Question 15

Larry's boat shop wants to monitor the number of blemishes in the paint of each boat.Construct a 3-sigma c-chart to determine if their paint process is in control using the following data.

Accepted Answer

@#IMG-DLM& @#IMG-DLM& The proc

Question 16

A retail store manager is trying to improve and control the rate at which cashiers sign customers up
for store credit cards.Suppose the manager takes 10 samples,each with 100 observations.The p-bar
value is found to be .05,and the manager does not want a lower limit below .0064.What z-value would this imply,and how confident can she be that the true lower limit is greater than or equal to .0064?

Accepted Answer

Sigma-p = sqrt ( .05*(1 - .05)/100)= .02

Question 17

The ________ is the percentage defective in an average lot of goods inspected through acceptance sampling.

Accepted Answer

AOQ or ave

Question 18

Assignable causes:

Accepted Answer

A) are not as important as natural causes. 
B) are within the limits of a control chart. 
C) depend on the inspector assigned to the job. 
D) are also referred to as "chance" causes. 
E) are causes of variation that can be identified and investigated. 
A) are not as important as natural causes. 
B) are within the limits of a control chart. 
C) depend on the inspector assigned to the job. 
D) are also referred to as "chance" causes. 
E) are causes of variation that can be identified and investigated.

Question 19

Which of the following is TRUE regarding the average outgoing quality level?

Accepted Answer

A) An AOQ value of 1 is ideal,because all defects have been removed. 
B) AOQ is always greater than AQL but less than LTPD. 
C) AOQ rises (worsens)following inspection of failed lots. 
D) AOQ is very low (very good)for extremely poor quality lots. 
E) None of the above is true. 
A) An AOQ value of 1 is ideal,because all defects have been removed. 
B) AOQ is always greater than AQL but less than LTPD. 
C) AOQ rises (worsens)following inspection of failed lots. 
D) AOQ is very low (very good)for extremely poor quality lots. 
E) None of the above is true.

Question 20

________ is a method of measuring samples of lots or batches of product against predetermined standards.

Accepted Answer

The answer of ________ is a method of measuring samples...

Exam 20: Statistical Process Control

An x-bar chart is used when we are sampling attributes.

Which of the following is true of a p-chart?

What is the statistical process chart used to control the number of defects per unit of output?

According to the text,what is the most common choice of limits for control charts?

A manufacturer uses statistical process control to control the quality of the firm's products.Samples of 50 of Product A are taken,and a defective/acceptable decision is made on each unit sampled.For Product B,the number of flaws per unit is counted.What type(s)of control charts should be used?

Mean charts and range charts complement one another,one detecting shifts in process average,the other detecting shifts in process dispersion.

If a sample of items is taken and the mean of the sample is outside the control limits,the process is:

What are the three possible results (or findings)from the use of control charts?

Ten samples of size four were taken from a process,and their weights measured.The sample averages and sample ranges are in the following table.Construct and plot an x-bar and R-chart using these data.Is the process in control?

The width of a bronze bar is intended to be one-eighth of an inch (0.125 inches).Inspection samples contain five bars each.The average range of these samples is 0.01 inches.What are the upper and lower control limits for the x-bar and R-chart for this process,using 3-sigma limits?

Acceptance sampling is usually used to control:

Larry's boat shop wants to monitor the number of blemishes in the paint of each boat.Construct a 3-sigma c-chart to determine if their paint process is in control using the following data.

The ________ is the percentage defective in an average lot of goods inspected through acceptance sampling.

Assignable causes:

Which of the following is TRUE regarding the average outgoing quality level?

________ is a method of measuring samples of lots or batches of product against predetermined standards.

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