Sampling is used to inspects
batches of products. To avoid calculation,
and negotiation, published standard sampling
plans are normally used. The most commonly
accepted sampling plan is ANSI/ASQ Z1.4-2003.
The figure shows an example of a page from
a sampling plan:
The first step is to find
the sample size code letter. This is obtained
from a separate table and is based on the
lot size and the severity of the inspection
required. A value for the AQL is also selected.
The table shown above is then
used to find the sample accept/reject values.
For example if the code letter were 'N'
and the AQL was 0.15 then the sample size
would be 500. The batch would be accepted
if there were 1 defect or less, and rejected
if there were two defects or more.