MULTIPLE CHOICE
1.Acceptance sampling
1.a. is the application of statistical techniques to the control of processes
2.b.was developed by Walter Shewhart of Bell Laboratories
3.c.is used to determine whether to accept or reject a lot of material based on the evaluation of a sample
4.d.separates the natural and assignable causes of variation
5.e.all of the above
2.Acceptance sampling's primary purpose is to
1.a.estimate process quality
2.b.estimate lot quality
3.c.detect and eliminate defectives
4.d.decide if a lot meets predetermined standards
5.e.determine whether defective items found in sampling should be replaced
3.An acceptance sampling plan's ability to discriminate between low quality lots and high quality lots is described by
1.a. a Gantt chart
2.b. the Central Limit Theorem
3.c. a process control chart
4.d. an operating characteristics curve
5.e. a range chart
4.Acceptance sampling
1.a. may involve inspectors taking random samples (or batches) of finished products and measuring them against predetermined standards
2.b.may involve inspectors taking random samples (or batches) of incoming raw materials and measuring them against predetermined standards
3.c.is more economical than 100% inspection
4.d.may be either of a variable or attribute type, although attribute inspection is more common in the business environment
5.e.All of the above are true.
5.Which of the following statements on acceptance sampling is true?
1.a.Acceptance sampling draws samples from a population of items, tests the sample, and accepts the entire population if the sample is good enough, and rejects it if the sample is poor enough.
2.b.The sampling plan contains information about the sample size to be drawn and the critical acceptance or rejection numbers for that sample size.
3.c.The steeper an operating characteristic curve, the better its ability to discriminate between good and bad lots.
4.d.All of the above are true.
5.e.All of the above are false.
6.Acceptance sampling is usually used to control
1.a. the number of units output from one stage of a process which are then sent to the next stage
2.b.the number of units delivered to the customer
3.c.the quality of work-in-process inventory
4.d.incoming lots of purchased products
5.e.all of the above
7.An operating characteristic (OC) curve describes
1.a. how many defects per unit are permitted before rejection occurs
2.b. the sample size necessary to distinguish between good and bad lots
3.c. the most appropriate sampling plan for a given incoming product quality level
4.d. how well an acceptance sampling plan discriminates between good and bad lots
5.e. none of the above
8.An operating characteristics curve shows
1.a. upper and lower product specifications
2.b. product quality under different manufacturing conditions
3.c. how the probability of accepting a lot varies with the population percent defective
4.d. when product specifications don't match process control limits
5.e. how operations affect certain characteristics of a product
9.Producer's risk is the probability of
1.a. accepting a good lot
2.b. rejecting a good lot
3.c. rejecting a bad lot
4.d. accepting a bad lot
5.e. none of the above
10.Which of the following is true regarding the relationship between AOQ and the true population percent defective?
1.a. AOQ is greater than the true percent defective.
2.b. AOQ is the same as the true percent defective.
3.c. AOQ is less than the true percent defective.
4.d. There is no relationship between AOQ and the true percent defective.
5.e. The relationship between these two cannot be determined.
11.Average outgoing quality (AOQ) usually
1.a. worsens with inspection
2.b. stays the same with inspection
3.c. improves with inspection
4.d. may either improve or worsen with inspection
5.e. is the average quality before inspection
12.A Type I error occurs when
1.a. a good lot is rejected
2.b. a bad lot is accepted
3.c. the number of defectives is very large
4.d. the population is worse than the AQL
5.e. none of the above
13.A Type II error occurs when
1.a. a good lot is rejected
2.b. a bad lot is accepted
3.c. the population is worse than the LTPD
4.d. the proportion of defectives is very small
5.e. none of the above
14.In most acceptance sampling plans, when a lot is rejected, the entire lot is inspected and all defective items are replaced. When using this technique the AOQ
1.a. worsens (AOQ becomes a larger fraction)
2.b. improves (AOQ becomes a smaller fraction)
3.c. is not affected, but the AQL is improved
4.d. is not affected
5.e. falls to zero
15.An acceptance sampling plan is to be designed to meet the organization's targets for product quality and risk levels. Which of the following is true?
1.a. n and c determine the AQL.
2.b. AQL, LTPD, α and β collectively determine n and c.
3.c. n and c are determined from the values of AQL and LTPD.
4.d. α and β are determined from the values of AQL and LTPD.
5.e. None of the above is true.
16.A lot that is accepted by acceptance sampling
1.a. has more defects than existed before the sampling
2.b. has had all its defects removed by 100% inspection
3.c. will have the same defect percentage as the LTPD
4.d. has no defects present
5.e. All of the above are false.
17.Which of the following statements about acceptance sampling is true?
1.a. The steeper an OC curve, the better it discriminates between good and bad lots.
2.b. Acceptance sampling removes all defective items.
3.c. Acceptance sampling of incoming lots is replacing statistical process control at the supplier.
4.d. Acceptance sampling occurs continuously along the assembly line.
5.e. All of the above are true.
18.Which of the following is true regarding the average outgoing quality level?
1.a. An AOQ value of 1 is ideal, because all defects have been removed.
2.b. AOQ is always greater than AQL but less than LTPD.
3.c. AOQ rises (worsens) following inspection of failed lots.
4.d. AOQ is very low (very good) for extremely poor quality lots.
5.e. None of the above is true.