ISPAM Meeting Book

9/17/2015

Four quantities are needed for the calculation of sample size: 3. The contamination rate that is considered unacceptable. The level at which one would want to take action. This is called the Rejectable Quality Level (RQL). 4. The error rate for not acting when the lot is at the RQL. This is the Type 2 error or Consumer’s risk. A typical Type 2 error is 10%. But AQL and RQL are currently 0 and 1

Statistical confidence based on sample numbers • Using Type 1 error rate of 5% and a Type 2 e o ate of 10% ith 60 samples the rr r r , w , “AQL” is 0.09% and the “RQL” is 3.8% (for a sampling plan that accepts with no positives and rejects with 1 positive) • If 0.09% of the individual samples are contaminated, 5% of the time the lot would be rejected. If 3.8% of the individual samples are contaminated, 10% of the time the lot would be accepted

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