In the purchase of lots of diffuser elements, the decision
to accept or reject a lot is often based on the results
of inspecting a random sample of articles from the
lot. When the decision to accept or reject a lot is based
on classification of the articles as either defective or
nondefective, the sampling plan is called inspection by
attributes. The lot is accepted if no more than an allowable
number of defective articles are found. A sampling
plan based on one sample is known as a single sampling
plan. Some saving of inspection costs can be achieved if
acceptance is based on two or more successively drawn
samples rather than one, Le., double or multiple sampling
plans. Acceptance sampling plans based on attributes
are detailed in Military Standard 105DA'.