Is complementary to ISO 2859. Object of the methods laid down is to ensure that lots of an acceptable quality have a high probability of acceptance and that the probability of rejection of inferior lots is as high as possible. To be used under the following conditions: inspection procedure to be applied to a continuous series of lots of discrete products supplied by one producer using one production process; only a single quality characteristic is considered which must be measurable on a continuous scale; production is stable and quality characteristic is distributed normally; a contract or standard defines an upper and/or a lower specification limit.