Question

1- When do we need to use the acceptance sampling?
2- What is the main difference between the single and double sampling plans?
3- What is the acceptance number?
4- What are the AQL and LTPD?
5- Explain the mechanism of the double sampling plan?
6- What is the difference between Pareto Diagram and acceptance samplin?

Answer 1

1.In general, acceptance sampling is employed when one or several of the following hold: testing is destructive; the cost of 100% inspection is very high; and. 100% inspection takes too long..

2.In single sampling plan the acceptance number is 2, sample size is 125 ie., If the number of defective items is 0 or 1 or 2, then the lot is accepted. In double sampling, 100 items are selected as first sample initially. If the number of defective items are 0 item or 1 item, then the will be accepted.

3.acceptance number. The highest number of defects that a sample of products from a manufacturing process can have in order for the inspection lot to be accepted. ... Many process improvement initiatives are often used to reduce the number of defects in a process in order to avoid exceeding the acceptance number.

4.The AQL is the maximum defect rate that is ACCEPTABLE to ship to your Customer. The RQL is the minimum Defect rate that not acceptable to ship; in other words it is the rate that you want to detect and reject. A LTPD plan is an RQL based plan.

5.Application of double sampling requires that a first sample of size n_1 is taken at random from the (large) lot. The number of defectives is then counted and compared to the first sample's acceptance number a_1 and rejection number r_1.

6.Pareto charts help us quickly see the order of many different factors contributing to a problem.