SKEDSOFT

The above can be only achieved by 100% inspection. Therefore the sampling inspection carries a risk of rejecting a good lot and accepting a bad lot. The producer risk (α) is the probability of rejection of good lot. The risk is frequently given as 0.05. But it can range from 0.01 to 0.1. Since α is expressed in terms of probability of rejection, it cannot be located on the OC Curve unless specified in terms of probability of acceptance. Thus the probability of acceptance = 1 – α (where α = 0.05). Curve is for N = 4000, n = 300, c = 4. The Pa is 0.95.

Associated with producer’s risk is (α) the numerical definition of a good quality which is called the Acceptance quality level. The AQL is the maximum  percentage defective that can be considered to be accepted. For the sampling plan, N = 4000, n = 300, c = 4 AQL = 0.7% for α = 0.05. In other words the product 0.7% defective (good quality) will have a rejcetion of probability of 0.05. The consumer’s risk (β) is the probability of accepting the bad lot. The risk is frequently given as 0.1. Since β is expressed in terms of probability of acceptance no conversion is necessary. Associated with the consumer’s risk is the numerical definition of the bad quality called RQL or LTPD. It is the percent defective in the lot which can be tolerated by the consumer. LTPD in this case is 2.6% for a β value of 0.10, lots that are 2.6% defective (bad quality) will have an acceptance probability of 0.1.