AQL Sampling (Z1.4)

ANSI/ASQ Z1.4 (ex MIL-STD-105) tells you how many parts to inspect from a lot. Enter the lot size and inspection level to get the sample-size code letter and sample size, then pick an accept number (Ac) and see the acceptance probability at your AQL (producer's risk) and at a reject quality (consumer's risk).

The exact tabulated Ac/Re for each AQL come from Z1.4 Table II-A; this evaluates any Ac you choose against the binomial OC curve.

Operating characteristic (OC) curve

Probability of accepting the lot as its true defect rate rises. The dashed line marks your AQL — a good plan accepts almost every lot there and rejects at the reject quality.