Deck 10: Extension: Acceptance Sampling

Question 1

Which of the following is associated with consumer's risk?

A) LTPD
B) AQL
C) AOQL
D) SPC
E) C_pk

Answer 1

LTPD

Question 2

A graphical representation that shows the risk of: (1) accepting bad lots and (2) rejecting good lots is called the:

A) indifference curve.
B) operating characteristic curve.
C) sampling plan.
D) inspection curve.
E) operating inspection plan.

Answer 2

operating characteristic curve.

Question 3

Sampling plans are designed considering both the cost and time required for the inspection.

Answer 3

True

Question 4

Acceptance sampling procedures can be applied to both attribute and variables inspection.

Question 5

Acceptance sampling procedures are applicable for inspection both before and after production.

Question 6

The purpose of acceptance sampling is to decide whether a batch of items satisfies pre-determined standards.

Question 7

Acceptance sampling is most useful when the cost consequences of passing defectives are low.

Question 8

Flexible acceptance sampling revises the sampling plan in response to actual results.

Question 9

When is the average outgoing quality level (AOQL) at its peak?

A) when the incoming fraction defective is at a minimum
B) when the incoming fraction defective is at a maximum
C) when the outgoing fraction defective is at a minimum
D) when the outgoing fraction defective is constant
E) when the outgoing fraction defective begins to increase

Question 10

In a single-sampling plan, the entire lot, or batch of items, is accepted or rejected based upon only one specified sized sample.

Question 11

A good sampling plan will occasionally reject a lot with very good quality.

Question 12

Acceptance sampling is a form of inspection applied to items during an ongoing process.

Question 13

The ability of an acceptance sampling plan to discriminate between good and bad lots is described by its operating characteristic curve.

Question 14

Suppose that only two incoming fraction defective levels, 4 percent and 8 percent, are possible. These incoming fraction defective levels are equally likely. At a 4 percent incoming fraction defective, there's a 60 percent chance that a lot will be accepted. At 8 percent incoming fraction defective, there's a 20 percent chance that a lot will be accepted. Lots that are not accepted are subject to 100 percent sorting. What is average outgoing quality?

A) 40 percent
B) 20 percent
C) 10 percent
D) 4 percent
E) 2 percent

Question 15

In a double-sampling plan, a second sample may not be taken if the results of the first sample are conclusive.

Question 16

Acceptance sampling is applied to batches of items during the production process.

Question 17

Which of the following is associated with producer's risk?

A) LTPD
B) AQL
C) AOQL
D) SPC
E) C_pk

Question 18

In a double-sampling plan, a second sample is taken if the results of the first sample are inconclusive.

Question 19

Acceptance sampling plans must specify the lot size, the sample size, and the acceptance/rejection criteria.

Question 20

A double-sampling plan requires a second sample of exactly twice the size of the first sample.

Question 21

The purpose of acceptance sampling is to:

A) estimate process quality.
B) estimate lot quality.
C) detect and eliminate defectives.
D) decide if a lot meets predetermined standards.
E) accept samples of products.

Question 22

Acceptance sampling plans might call for the selection of:

A) one or more samples.
B) a variable number of samples based on actual results.
C) random inspections.
D) outside audits by testing agencies.
E) 100 percent inspection.

Question 23

A quality inspector for Alpha-Beta Co. is concerned about the quality of the batch of several thousand blank DVD disks which his company produced this week and is preparing to ship. If he uses an acceptance sampling plan of n = 5 and c = 2, what will be the average outgoing quality for batches with 40 percent defectives?

A) .1270
B) .2730
C) .3174
D) .6826
E) .7270

Question 24

Suppose that only two incoming fraction defective levels, 2 percent and 6 percent, are possible. The 2 percent incoming fraction defective level is twice as likely as the 6 percent. At a 2 percent incoming fraction defective, there's an 80 percent chance that a lot will be accepted. At 6 percent incoming fraction defective, there's a 20 percent chance that a lot will be accepted. Lots that are not accepted are subject to 100 percent sorting. What is average outgoing quality (approximately)?

A) 1.60 percent
B) 1.47 percent
C) 1.20 percent
D) .73 percent
E) .80 percent

Question 25

A quality inspector for Alpha-Beta Co. is concerned about the quality of the batch of several thousand blank DVD disks which his company produced this week and is preparing to ship. If the cost of replacing a defective DVD disk once it has been shipped is $2.00, while the cost of 100 percent inspection prior to shipment is $.40 each, at what point is he indifferent between 100 percent inspection and shipment without inspection?

A) 0 percent defectives
B) 2 percent defectives
C) 5 percent defectives
D) 20 percent defectives
E) 30 percent defectives

Question 26

A Type II (beta) error occurs when:

A) a bad lot is accepted.
B) a good lot is rejected.
C) a bad lot is rejected.
D) a good lot is accepted.
E) a rejected lot is reinspected.

Question 27

An OC curve shows:

A) average outgoing quality.
B) the average outgoing quality limit.
C) out-of-control criteria.
D) operating control.
E) probability of acceptance versus lot quality.

Question 28

Which one of the following would not be a reason for using acceptance sampling?

A) high cost of passing defectives
B) large number of items
C) destructive testing
D) boredom and fatigue that would accompany complete inspection
E) low cost of passing defectives

Question 29

A quality inspector for Alpha-Beta Co. is concerned about the quality of the batch of several thousand blank DVD disks which his company produced this week and is preparing to ship. If, based on his acceptance sample, he decides to ship this batch without inspection, which type error would be possible?

A) inspector's error
B) producer's error
C) Type I error
D) Type II error
E) both Type I and Type II errors

Question 30

An AOQ curve shows:

A) the maximum quality.
B) average outgoing quality relative to incoming quality.
C) how well a sampling plan can discriminate between good and bad lots.
D) the actual quality level.
E) "good" quality.

Question 31

Sampling plans typically specify:

A) lot size.
B) sample size.
C) number of samples to be taken.
D) acceptance/rejection criteria.
E) all choices are correct.

Question 32

A lot can be "accepted" or "rejected" in a multiple-sampling plan:

A) after one sample is taken.
B) after two samples are taken.
C) after three or more samples are taken.
D) all of the choices.
E) none of the choices.

Question 33

A Type I (alpha) error occurs when:

A) a bad lot is accepted.
B) a good lot is rejected.
C) a bad lot is rejected.
D) a good lot is accepted.
E) an accepted lot is reinspected.

Question 34

The quality manager for Graphics, Inc., is concerned about the quality of the lot of several thousand posters which her company printed this week and is now preparing to ship. If she uses an acceptance sampling plan of n = 10 and c = 2, what is the probability that, if this lot is 10 percent defective, it will be accepted for shipment without inspection?

A) .9298
B) .0702
C) .8189
D) .2198
E) .5995

Question 35

In acceptance sampling, the level of inspection automatically adjusts to the quality of lots being inspected, assuming that:

A) a single-sampling plan is used.
B) double-sampling plans are used.
C) multiple-sampling plans are used.
D) "rejected" lots are subjected to 100 percent inspection.
E) the incoming fraction defective remains constant.

Question 36

The quality manager for Graphics, Inc., is concerned about the quality of the lot of several thousand posters which her company printed this week and is now preparing to ship. If the cost of replacing a defective poster once it has been shipped is $10.00, while the cost of complete 100 percent inspection prior to shipment is $.50 per poster, at what point is she indifferent between complete inspection and shipment without inspection?

A) 5 percent
B) 10 percent
C) 12 percent
D) 20 percent
E) 25 percent

Question 37

The ability of a sampling plan to discriminate between lots of high quality and lots of low quality is described by:

A) a Gantt chart.
B) an operating characteristic curve.
C) an average outgoing quality curve.
D) a process control chart.
E) a range chart.

Question 38

The AQL indicates:

A) acceptable quality level.
B) average quality level.
C) actual quality level.
D) aggregate quality level.
E) approximate quality level.

Question 39

A quality inspector for Alpha-Beta Co. is concerned about the quality of the batch of several thousand blank DVD disks which his company produced this week and is preparing to ship. If he uses an acceptance sampling plan of n = 5 and c = 2, what is the probability that, if this batch is 40 percent defective, it will be rejected and receive 100 percent inspection prior to shipment?

A) .1270
B) .2730
C) .3174
D) .6826
E) .7270

Question 40

A lot can be "accepted" or "rejected" in a double-sampling plan:

A) after one sample is taken.
B) after two samples are taken.
C) only after two samples are taken.
D) All choices are correct.
E) Only after one and after two samples are taken is correct.

Question 41

The quality manager for Microelectronics, Inc., is concerned about the quality of the batch of several thousand Z-box games which his company is about to ship. If, based on his acceptance sample, he decides to ship this batch without inspection, which type error would be possible?

A) inspector's error
B) producer's error
C) Type I error
D) Type II error
E) both Type I and Type II errors

Question 42

The quality manager for Microelectronics, Inc., is concerned about the quality of the batch of several thousand Z-box games which his company is about to ship. If he uses an acceptance sampling plan of n = 20 and c = 1, what is the probability that, if this batch is 15 percent defectives, it will be rejected and completely inspected prior to shipment?

A) .0263
B) .1237
C) .1756
D) .8244
E) .9737

Question 43

Suppose we have a lot of several thousand units of a finished good. If this lot were 5 percent defective, what type error would be possible? For an acceptance sampling plan with n = 20 and c = 2, what would be the risk of this error?

Question 44

Suppose we have a lot of several thousand units of a finished good. If n = 20 and c = 2, what is the probability that, if this lot were 5 percent defective, it would be rejected and completely inspected prior to shipment? 10 percent defective? 15 percent? 20 percent?

Question 45

The quality manager for Graphics, Inc., is concerned about the quality of the lot of several thousand posters which her company printed this week and is now preparing to ship. If, based on her acceptance sample, she decides to ship this lot without inspection, which type error would be possible?

A) Type I
B) Type II
C) both Type I and Type II errors
D) neither Type I nor Type II error
E) cannot be determined without further data

Question 46

The quality manager for Microelectronics, Inc., is concerned about the quality of the batch of several thousand Z-box games which his company is about to ship. If he uses an acceptance sampling plan of n = 20 and c = 1, what will be the average outgoing quality for batches with 15 percent defectives?

A) .0263
B) .1237
C) .1756
D) .8244
E) .9737

Question 47

The quality manager for Graphics, Inc., is concerned about the quality of the lot of several thousand posters which her company printed this week and is now preparing to ship. If she uses an acceptance sampling plan of n = 10 and c = 2, what will be the average outgoing quality for lots with 20 percent defectives?

A) .13556
B) .20000
C) .23630
D) .58434
E) .32484

Question 48

The quality manager for Frozen Pizzas, Inc., is concerned about the quality of the lot of several thousand pizzas which his company produced this week, and is now ready to ship. If he uses an acceptance sampling plan of n = 8 and c = 1, what will be the average outgoing quality for lots with 10 percent defectives?

A) .0813
B) .0962
C) .1869
D) .7318
E) .8131

Question 49

Suppose we have a lot of several thousand units of a finished good. For an acceptance sampling plan with n = 20 and c = 2, what will be the average outgoing quality for lots with 5 percent defectives? 10 percent? 15 percent? 20 percent?

Question 50

The quality manager for Frozen Pizzas, Inc., is concerned about the quality of the lot of several thousand pizzas which his company produced this week, and is now ready to ship. If he uses an acceptance sampling plan of n = 8 and c = 1, what is the probability that, if this lot is 15 percent defective, it will be rejected and completely inspected prior to shipment?

A) .8948
B) .8131
C) .6572
D) .5033
E) .3428

Question 51

Suppose we have a lot of several thousand units of a finished good. If n = 20 and c = 2, what is the probability that, if this lot were 5 percent defective, it would be accepted for shipment without inspection? 10 percent defective? 15 percent? 20 percent?

Question 52

Suppose we have a lot of several thousand units of a finished good. If this lot were 20 percent defective, what type error would be possible? For an acceptance sampling plan with n = 20 and c = 2, what would be the risk of this error?

Question 53

A manufacturer purchases large quantities of metal brackets from several suppliers. The brackets are shipped in lots of 8,000 each. Random samples of 40 brackets are taken from each lot, and the lot is rejected if any defectives are discovered. Rejected lots are subjected to 100 percent inspection, and any defectives are replaced with good brackets. Determine the average outgoing quality limit for this sampling plan.

Question 54

Given the following acceptance sampling data for a lot of several thousand units of a finished good:
Per-unit cost of replacing a defective unit after it has been shipped is $5.00
Per-unit cost of 100 percent inspection prior to shipment is $.60.
What is the point of indifference between 100 percent inspection and shipment without inspection?

Question 55

The quality manager for Frozen Pizzas, Inc., is concerned about the quality of the lot of several thousand pizzas which his company produced this week, and is now ready to ship. If the cost of replacing a defective pizza once it has been shipped is $5.00, while the cost of complete (100 percent) inspection prior to shipment is $.30 per pizza, what is the point of indifference between complete inspection and shipment without inspection?

A) 1.67 percent defectives
B) 3 percent defectives
C) 5 percent defectives
D) 6 percent defectives
E) 16.7 percent defectives

Question 56

A firm that makes plastic wrapping material takes random samples of 50 items from each lot before it is sent to a customer. Lots contain 2,000 items each. Any lot with more than one defective is subjected to 100 percent inspection, and any defectives are replaced with good ones.
(A) Construct the OC curve for this plan.
(B) Construct the AOQ curve for this plan. What is the approximate AOQ limit?

Question 57

The quality manager for Graphics, Inc., is concerned about the quality of the lot of several thousand posters which her company printed this week and is now preparing to ship. If the indifference point between complete inspection and shipment without inspection is 12 percent defectives, and she decides to sample 15 posters (n = 15), what is the maximum number of sample defectives (c) for which this lot would be accepted for shipment without further inspection?

A) 0 defectives
B) 1 defective
C) 2 defectives
D) 3 defectives
E) 4 defectives

Question 58

The quality manager for Microelectronics, Inc., is concerned about the quality of the batch of several thousand Z-box games which his company is about to ship. If the cost of replacing a defective Z-box game once it has been shipped is $5.00, while the cost of complete (100 percent) inspection prior to shipment is $.20 each, at what point is he indifferent between complete inspection and shipment without inspection?

A) 0 percent defectives
B) 4 percent defectives
C) 5 percent defectives
D) 9 percent defectives
E) 22 percent defectives

Question 59

Shipments of bowling balls are sampled before delivery to a warehouse. Lots of 600 balls are checked, using 10 observations from each lot. Any lot with more than one defective is rejected. Calculate values for the operating characteristic curve for this sampling plan.

Question 60

The quality manager for Frozen Pizzas, Inc., is concerned about the quality of the lot of several thousand pizzas which his company produced this week, and is now ready to ship. If he uses an acceptance sampling plan of n = 8 and c = 1, what is the probability that, if this lot is 10 percent defective, it will be accepted for shipment without inspection?

A) .9619
B) .9428
C) .8131
D) .4305
E) .1869

Question 61

Suppose a batch is of unacceptable quality. There is a 10 percent chance that it will be accepted. Thus, ________ is 10 percent.

Question 62

Suppose a batch is of acceptable quality. There is a 10 percent chance that it will be rejected. Thus, ________ is 10 percent.

Question 63

A firm uses acceptance sampling to evaluate batches of inputs. Ideally, the defect rate would be no more than 3.5 percent. The firm knows that on occasion, batches with that defect rate or higher might be rejected. However, if the defect rate is less than or equal to 3.5 percent, the firm would like there to be very little chance of that batch being rejected. This value, 3.5 percent, is the firm's:

Question 64

If the value for average outgoing quality increases, this means that __________ defective units are being passed on.

Question 65

A firm uses acceptance sampling to evaluate batches of inputs. Ideally, the defect rate would be no more than 3.5 percent. The firm knows that on occasion, batches with higher defect rates will be accepted. However, if the defect rate reaches 7 percent, the firm would like there to be very little chance of that batch being accepted. This value, 7 percent, is the firm's: