Question

Explain acceptance sampling: What are the types of acceptance sampling? Under what conditions is acceptance sampling accepted and not accepted? What are advantages and disadvantages of acceptance sampling?

Answer 1

• Acceptance sampling is a statistical measure to determine whether to accept or reject a production lot of material. Acceptance sampling helps to determine the quality of products by selecting a specified number of sample for testing. Product are chosen randomly for testing defects. On the basis of sampling company can decide whether to accept or reject a lot.
• The information from inspected sample allows to make decision of acceptance or rejection. If the product conforms to the given specification it is accepted and it is rejected if the product do not conform to the given specification .

Types of acceptance sampling

• Single sampling plan
Single sampling plans involves selecting one sample of items at random from a lot and the disposition of the lot is determined from the resulting information.

• Double sampling plans
There are three possibilities apta the testing of first sample :
1. Accept the lot
2. Reject the lot
3. No Decision
Second sample is taken when the outcome is no decision. Then the procedure is to combine results of both sample and make a final decision of acceptance or rejection based on that information.

• Multiple sampling plan
Multiple sampling plan is an extension of double sampling plan where more than two samples are taken to draw a conclusion.

• Sequential sampling plans
Sequential sampling plan is the ultimate extension of multiple sampling where samples are selected from a lot one at a time and after inspection of each item a decision of acceptance or rejection is made.

Advantages of acceptance sampling

• Acceptance sampling is economical and less time consuming than 100% inspection.
• Computation works are relatively less.
• Involves only less number of staff for inspection.
• Products of destructive nature can be inspected easily
• Scheduling and delivery times are improved due to quick inspection process

Disadvantages

• Success of system is directly related with sampling randomness
• Acceptance sampling does not provide 100% assurance for the confirmation of specification. There is always a risk of drawing from conclusion about the quality of product.