Contents
- Index
Single Sampling Plan for Defective Units
Characteristic:
Defective units
Assumptions:
(1) Representative sample
Parameters:
n = sample size, integer satisfying n>0
a = accept number, integer satisfying a³0 and a<n
Sometimes a third parameter, r = reject number, is given. The parameter r is always equal to a+1 and is redundant.
Procedure:
(1) Take a representative sample of n units from the lot to be inspected.
(2) Count the number of defective units in the sample.
(3) If this count is less than or equal to a, accept the lot. Otherwise reject the lot.
Sometimes the accept or reject decision is determined before all units are inspected. In this case, the inspection can be curtailed. For single sampling plans for defective units you can curtail on acceptance, rejection or both as follows:
Curtail on Rejection: Stop the inspection and reject as soon as a+1 defective units are found.
Curtail on Acceptance: Stop the inspection and accept as soon as n-a good units are found.
Full Curtailing: Perform both curtailing on acceptance and rejection.