Deck 19: Acceptance Sampling Plans

Question 1

The lot tolerance proportion defective (LTPD)is the customer's desired level of quality.

Answer 1

False

Question 2

A double-sampling plan has n1 = 50,n2 = 100,c1 = 2,and c2 = 4.Suppose on the first sample,five defectives were discovered.How many total items will be inspected before a decision is reached?

A)50
B)100
C)150
D)This cannot be determined with the information provided.

Answer 2

A

Question 3

An operating characteristic curve is a plot of the probability of accepting the lot against the proportion defectives.

Answer 3

True

Question 4

As more firms initiate total quality management systems,the need for acceptance sampling will increase.

Question 5

Lot tolerance proportion defective (LTPD)can be defined as

A)the quality level desired by the consumer.
B)the worst quality level the consumer can tolerate.
C)the probability of rejecting a good lot (i.e. ,when a lot is,in fact,acceptable to the consumer).
D)the probability of accepting a bad lot (i.e. ,when a lot is,in fact,not acceptable to the consumer).

Question 6

The distance between 1.0 and where the AQL intersects the OC curve is the value β (Beta).

Question 7

Which of the following statements is TRUE?

A)Sequential-sampling plans are preferred to single-sampling plans because the average number of items inspected is generally lower.
B)With a sequential-sampling plan,each time an item is inspected,a decision is made to accept or reject a lot.
C)With a sequential-sampling plan,sampling continues until the lot is rejected.
D)Sequential-sampling plans are defined by four parameters: n1,n2,c1,c2.

Question 8

Rectified inspection occurs when all defective items in the lot are replaced with good items if the lot is rejected and any defective items in the samples are replaced if the lot is accepted.

Question 9

A double-sampling plan has n1 = 50,n2 = 100,c1 = 2,and c2 = 4.Suppose the first sample revealed two defectives.What should be done?

A)Reject the entire lot.
B)Take a second sampling of 100 units.
C)Accept the entire lot.
D)Repeat the tests on the first sample.

Question 10

Acceptance sampling is an inspection procedure used to determine whether to accept or reject a specific quantity of material.

Question 11

Which of the following is an example of a type II error?

A)Convicting an innocent defendant
B)Returning your "dead" stereo for warranty repair when its malfunction was caused by it not being plugged in
C)Halting production to adjust a machine when your process was actually in control
D)Eating food laden with salmonella

Question 12

For a given AQL and LTPD,which one of the following statements about the single-sampling plan is TRUE?

A)If c stays constant but n is increased,both the producer's risk and the consumer's risk will increase.
B)If c stays constant but n is increased,both the producer's risk and the consumer's risk will decrease.
C)If n stays constant but c is increased,the producer's risk will decrease and the consumer's risk will increase.
D)If n stays constant but c is increased,the producer's risk will increase and the consumer's risk will decrease.

Question 13

A double-sampling plan has n1 = 50,n2 = 100,c1 = 2,and c2 = 4.Suppose on the first sample,one defective item was discovered.What should be done?

A)Reject the entire lot.
B)Take a second sample of 100 units.
C)Accept the entire lot.
D)Repair the defective units,and accept the entire lot.

Question 14

If the sample size is increased and the acceptance level is unchanged,the OC curve will have a higher consumer's risk.

Question 15

Which of the following is an example of a type I error?

A)Buying a carton of eggs at the store and discovering that one was broken
B)Releasing a guilty defendant
C)Returning your computer for warranty repair when the fault was caused by user error
D)Passing defective materials from a supplier into your processes to keep your workers busy

Question 16

The chance that perfectly good material will be rejected based on a sample is known as a type I error.

Question 17

Acceptable quality level can be defined as the

A)quality level desired by the consumer.
B)worst quality level the consumer can tolerate.
C)probability of rejecting a good lot (i.e. ,when a lot is,in fact,acceptable to the consumer).
D)probability of accepting a bad lot (i.e. ,when a lot is,in fact,not acceptable to the consumer).

Question 18

Increasing c while holding n constant decreases the producer's risk and increases the consumer's risk.

Question 19

A single-sampling plan has n = 200 and c = 6.A sample is taken and five items are found to be defective.What should be done?

A)Another sample should be taken.
B)The lot should be rejected.
C)The lot should be accepted.
D)The five items should be repaired,and then the entire lot should be accepted.

Question 20

A sequential sampling plan generally lowers the ANI.

Question 21

A quality manager has established a sampling plan that calls for a sample size of 100 units and an acceptance number of 2.The supplier has agreed to a contract that calls for an AQL of 0.01 and an LTPD of .05.Which of the following statements is TRUE? Table I.1 is appended to this exam.

A)Lowering the acceptance number to 1 will raise the probability of a type II error.
B)Increasing the sample size will increase α.
C)Raising the AQL to 0.02 will lower the chance of a type I error.
D)Reducing the LTPD to 0.04 will reduce the chance of a type II error.

Question 22

A quality manager has established a sampling plan that calls for a sample size of 50 units and an acceptance number of 2.The supplier has agreed to a contract that calls for an AQL of 0.02 and an LTPD of .07.What is the producer's risk? Table I.1 is appended to this exam.

A)Less than 0.07
B)Between 0.07 and 0.09
C)Between 0.09 and 0.11
D)Greater than 0.11

Question 23

Which one of the following will increase the consumer's risk?

A)Decrease sample size and hold constant the number of defective items in a sample.
B)Decrease the acceptable number of defective items in a sample and hold constant the sample size.
C)Increase the sample size and decrease the acceptable number of defective items in a sample.
D)Decrease the acceptable quality level and hold constant both sample size and the acceptable number of defective items in a sample.

Question 24

The quality manager has fixed n = 20 and c = 2 for a single-attribute sampling plan.Given AQL = 0.01 and LTPD = 0.05,what is the producer's risk? Table I.1 is appended to this exam.

A)Between 0.0001 and 0.01
B)Between 0.01 and 0.1
C)Between 0.99 and 0.9999
D)Between 0.9 and 0.99

Question 25

Table I.1

A single-sampling plan by attributes is needed for a purchased component.Given the following information,what is the consumer's risk β? Table I.1 is above. Sample size = 50
Acceptance number (c)= 3
Acceptance quality level (AQL )= 0.01
Lot tolerance proportion defective (LTPD)= 0.04

A)Greater than or equal to 0 but less than or equal to 0.25
B)Greater than 0.25 but less than or equal to 0.50
C)Greater than 0.50 but less than or equal to 0.75
D)Greater than 0.75 but less than or equal to 1.00

Question 26

A quality manager has established a sampling plan that calls for a sample size of 200 units and an acceptance number of 3.The supplier has agreed to a contract that calls for an AQL of 0.01 and an LTPD of .03.What is the producer's risk? Table I.1 is appended to this exam.

A)More than 0.14
B)Between 0.14 and 0.12
C)Between 0.12 and 0.10
D)Less than 0.10

Question 27

Which one of the following alternatives will reduce the producer's risk for a given AQL and LTPD?

A)Reduce n and keep c constant.
B)Increase n and keep c constant.
C)Increase n and reduce c.
D)Increase alpha.

Question 28

An item is purchased with one surface polished to a specified finish quality.From each incoming shipment,a sample of items is randomly selected and the polished surface of each sample item is compared with a standard and judged to be either acceptable or unacceptable.The following parameters have been established: AQL = 0.02,= 0.05,LTPD = 0.09,and = 0.10.Table I.1 is appended to this exam.What are the sample size and the acceptance number?

A)n = 89,c = 4
B)n = 39,c = 1
C)n = 43,c = 1
D)n = 237,c = 15

Question 29

A sample of 100 items is randomly selected from a shipment of incoming materials.AQL and LTPD have been established at 0.01 and 0.07,respectively.When four or more defective items are found in a sample,the shipment is rejected.Table I.1 is appended to this exam.What is the value of α?

A)Less than or equal to 0.04
B)Greater than 0.04 but less than or equal to 0.06
C)Greater than 0.06 but less than or equal to 0.08
D)Greater than 0.08

Question 30

A company wants to develop an acceptance sampling plan that keeps the producer's risk at 0.03 or less and the customer's risk at 0.10 or less.The acceptable quality level (AQL)is 0.01,and the lot tolerance proportion defective (LTPD)has been set at 0.10.Which one of the following plans gives us the desired protection? Table I.1 is appended to this exam.

A)c = 3,n = 190
B)c = 2,n = 54
C)c = 1,n = 30
D)c = 1,n = 20

Question 31

A quality manager has established a sampling plan that calls for a sample size of 200 units and an acceptance number of 3.The supplier has agreed to a contract that calls for an AQL of 0.01 and an LTPD of .03.What is the consumer's risk? Table I.1 is appended to this exam.

A)Less than 0.14
B)Between 0.14 and 0.15
C)Between 0.15 and 0.16
D)Greater than 0.16

Question 32

The average outgoing quality (AOQ)is

A)the average number of good units produced per hour.
B)the expected proportion of defects a sampling plan will allow.
C)the level of quality desired by the customer.
D)the worst level of quality tolerated by the consumer.

Question 33

Which one of the following actions will decrease the producer's risk?

A)Increase n and keep c constant.
B)Decrease n and keep c constant.
C)Keep n constant and decrease c.
D)Increase n and decrease c.

Question 34

The management of a company wishes to develop a new acceptance sampling plan that keeps acceptable quality level,lot tolerance proportion defective,and c constant.If the sample size (n)is increased,compared to the prior plan,which of the following is TRUE?

A)α increases
B)α decreases
C)β increases
D)α and β increase

Question 35

Use Table I.1 for the following question.What is the acceptance number of a single-sampling plan if n = 400,AQL = 0.002,and β = 0.01?

A)c = 0
B)c = 1
C)c = 2
D)c = 3

Question 36

A company is developing an acceptance sampling plan to monitor quality.The acceptable quality level (AQL)is 0.01,and a sampling plan having c = 5 is being considered.If a producer's risk of 0.03 is desired,what should be the sample size? Table I.1 is appended to this exam.

A)Less than or equal to 25
B)More than 25 but less than or equal to 175
C)More than 175 but less than or equal to 325
D)More than 325

Question 37

Use Table I.1 for the following question.What is the acceptance number of a single-sampling plan if n = 300,LPTD = 0.02,and β = 0.15?

A)c = 0
B)c = 1
C)c = 2
D)c = 3

Question 38

Which one of the following alternatives will reduce the consumer's risk for a given AQL and LTPD?

A)Reduce n and keep c constant.
B)Increase n and keep c constant.
C)Reduce n and increase c.
D)Increase beta.

Question 39

A quality manager has established a sampling plan that calls for a sample size of 50 units and an acceptance number of 1 The supplier has agreed to a contract that calls for an AQL of 0.02 and an LTPD of .07.What is the consumer's risk? Table I.1 is appended to this exam.

A)Less than 0.08
B)Between 0.08 and 0.10
C)Between 0.10 and 0.12
D)Greater than 0.12

Question 40

A manufacturer wants a sampling plan in which AQL = 0.02,LPTD = 0.12,α = 0.05,and β = 0.10.Which of the following values for n and c best satisfy these specifications? Table I.1 is appended to this exam.

A)n = 54,c = 3
B)n = 100,c = 2
C)n = 200,c = 1
D)n = 162,c = 0

Question 41

This OC curve represents a sampling plan developed for a lot size of 500,a sample size of 15,and an acceptance number of 2.The probability of acceptance for each of the first six points appears next to the plotted point.What is the average outgoing quality for an incoming fraction defective of 0.15?

A)Less than 0.06.
B)Greater than or equal to 0.06 but less than 0.07.
C)Greater than or equal to 0.07 but less than 0.08.
D)Greater than or equal to 0.08.

Question 42

A lot of 1,000 items is on the loading dock.A single-sampling plan calls for a sample size of 10.The following table gives the probability of acceptance for the plan over a range of possible quality levels. What is the average outgoing quality limit for this plan?

A)Less than or equal to 0.018
B)Greater than 0.0180 but less than or equal to 0.0200
C)Greater than 0.0200 but less than or equal to 0.0220
D)Greater than 0.0220

Question 43

________ is the worst level of quality that the customer can tolerate.

Question 44

A sample of 100 items is randomly selected from a shipment of incoming materials.AQL and LTPD have been established at 0.01 and 0.07,respectively.When four or more defective items are found in a sample,the shipment is rejected.Table I.1 is appended to this exam.What is the value of β?

A)Less than or equal to 0.05
B)Greater than 0.05 but less than or equal to 0.10
C)Greater than 0.10 but less than or equal to 0.15
D)Greater than 0.15

Question 45

A single-sampling plan using a sample size of 50 has the following performance: If the plan is used on a lot of 2,000 items,what is the average outgoing quality limit?

A)Less than or equal to 0.0240
B)Greater than 0.0240 but less than or equal to 0.0260
C)Greater than 0.0260 but less than or equal to 0.0280
D)Greater than 0.0280

Question 46

________ is the risk that a lot with LTPD will be accepted-a type II error.

Question 47

The average outgoing quality (AOQ)is

A)the proportion of defectives that the sampling plan will allow to pass.
B)the proportion of non-defectives that the sampling plan will allow to pass.
C)the highest proportion of defectives that the sampling plan will allow to pass.
D)the lowest proportion of defectives that the sampling plan will allow to pass.

Question 48

This OC curve represents a sampling plan developed for a lot size of 1000,a sample size of 15,and an acceptance number of 2.The probability of acceptance for each of the first six points appears next to the plotted point.What is the average outgoing quality for an incoming fraction defective of 0.25?

A)Less than 0.045.
B)Greater than or equal to 0.045 but less than 0.055.
C)Greater than or equal to 0.055 but less than 0.065.
D)Greater than or equal to 0.065.

Question 49

A lot of 2,000 items has just arrived.A single sampling calls for a sample size of 100 and c = 3.What is the average outgoing quality limit,assuming that all defectives in the entire lot are replaced if it is rejected and all defectives are replaced in the sample if it is accepted? Table I.1 is appended to this exam.

A)Less than or equal to 0.0150
B)Greater than 0.0150 but less than or equal to 0.0175
C)Greater than 0.0175 but less than or equal to 0.0200
D)Greater than 0.0200

Question 50

A double-sampling plan has a lower ________ than a single-sampling plan.

Question 51

A(n)________ is when the consumer randomly selects items from the lot and inspects them one by one.

Question 52

A single-sampling plan has the following performance: What is the average outgoing quality limit if the sample size is 200 and the lot size is 6,000?

A)Less than or equal to 0.0200
B)Greater than 0.0200 but less than or equal to 0.0220
C)Greater than 0.0220 but less than or equal to 0.0230
D)Greater than 0.0230

Question 53

This OC curve represents a sampling plan developed for a lot size of 500,a sample size of 15,and an acceptance number of 2.The probability of acceptance for each of the first six points appears next to the plotted point.What is the average outgoing quality limit?

A)Less than 0.08.
B)Greater than or equal to 0.08 but less than 0.09.
C)Greater than or equal to 0.09 but less than 0.10.
D)Greater than or equal to 0.10.

Question 54

________ is an inspection procedure used to determine whether to accept or reject a specific quantity of material.

Question 55

________ is the quality level desired by the consumer.

Question 56

A rectified inspection plan requires that

A)a rejected lot be returned to the supplier.
B)a rejected lot be subjected to 100% inspection.
C)a sample with too many defectives be returned to the lot for mixing and resampling.
D)all units in the sample be returned to the lot if it is rejected.

Question 57

This OC curve represents a sampling plan developed for a lot size of 1000,a sample size of 15,and an acceptance number of 2.The probability of acceptance for each of the first six points appears next to the plotted point.What incoming fraction defective is associated with the average outgoing quality limit?

A)0.10
B)0.15
C)0.20
D)0.25

Question 58

A single-sampling plan using a sample size of 50 on a lot size of 2,000 has the following performance: Today the company making the purchase receives two lots of 2,000 items and the inspection department is in a big hurry.Which action will result in an identical AOQL for the purchasing company?

A)Take a random sample of 25 from each lot and accept or reject both lots based on the results.
B)Take a random sample of 50 from one lot and accept or reject the second lot based on the first lot's results.
C)Take a random sample of 100 from one lot and accept or reject the second lot based on the first lot's results.
D)Take a random sample of 50 from each lot and accept or reject each lot based on the results.

Question 59

Champion Cooling Company has developed a sampling plan calling for a sample size of 25 and an acceptance number of 1.The proportion defective and probability of acceptance appear in the table.Floyd Electric,their supplier ships whatever Champion Cooling asks;sometimes the lot size is as small as 30 units and it has been as large as 10,000 units.Champion Cooling decides to stick with what they know,a sample size of 25 and an acceptance number of 1 despite advice to the contrary.Which statement regarding their sampling plan is best?

A)The average outgoing quality level will remain constant since the sample size and the acceptance number do not change.
B)The average outgoing quality level will vary as the lot size varies,but the average outgoing quality limit will remain constant.
C)The incoming fraction defective that produces the average outgoing quality limit will remain the same regardless of lot size.
D)The incoming fraction defective that produces the average outgoing quality limit will vary as the lot size varies.

Question 60

________ is the risk that the sampling plan will fail to verify an acceptable lot's quality and thus reject it-a type I error.

Question 61

Table I.1

A single-sampling plan by attributes is needed for a purchased component.Table I.1 is above.
Sample size = 100
Acceptance number (c)= 2
Acceptance quality level (AQL)= 0.01
Lot tolerance proportion defective (LTPD)= 0.04
Given the preceding information:
a.What is the producer's risk,α?
b.What is the consumer's risk,β?
c.Draw the OC curve for this plan.

Question 62

A small ________ can be disregarded in AOQ calculations involving an extremely large lot size.

Question 63

Discuss the two incorrect conclusions that can be made when using acceptance sampling.

Question 64

Replacing all defective items in a rejected lot and all defective items in a sample with good items is called ________ inspection.

Question 65

The AOQ is often lower for a supplier with a high fraction defective than for a supplier with a comparatively lower fraction defective.Why wouldn't a supplier with a lower fraction defective always have a better AOQ?

Question 66

The maximum value of the average outgoing quality over all possible values of the proportion defective is called the ________.

Question 67

If you were interested in minimizing the average number of items inspected,which sampling plan would you choose? Why?

Question 68

This OC curve represents a single sampling plan conducted on a lot size of 200 with a sample size of 20 and an acceptance number of 1.The y-coordinates of the first few points have been labeled;the x coordinates appear on the x-axis.If the receiving company uses rectified inspection,what is the greatest fraction defective that will enter their production process?

Question 69

Why is an operating-characteristic (OC)curve useful?

Question 70

Relative to an acceptance sampling plan,what is the net effect of increasing n while holding c constant?

Question 71

Increasing c while holding n constant decreases the ________ risk and increases the ________ risk.