N.Q.A.

This field displays the acceptable quality level.

Example:

From a 10,000 to 20,000 item production interval, a sampling of 20 items is removed.

These 20 items are evaluated according to degree of acceptance, when, for each degree a nonconformance item limit is set; if for each 20 parts, 4 of them represent problems, the sample is approved.

If the number of problematic parts (4, in the example) is greater than the limit, the part is rejected.