ISO 8423:1991

Sequential sampling plans for inspection by variables for percent nonconforming (known standard deviation)

Applies if all of the following conditions are satisfied: a) inspected are continuing series of lots of discrete items supplied by one producer from one production process; b) only a single quality characteristic x is taken into consideration; c) production is stable and x has a known standard deviation; d) an upper or lower limit (or both) is defined.