1.4 SINGLE/DOUBLE/MULTIPLE SAMPLED PLANS

 

• SINGLE - just take a sample from the lot, examine, and reject. e.g. a lot of 5000 has 200 samples removed, if more than 2 non-conforming samples found, the lot is sent back.

 

• DOUBLE - One sample is taken. If it conforms, keep the lot. If there are too many non-conforming send back the lot, otherwise take a second sample. If the combined first and second samples have too many rejects, then send the lot back.

 

• MULTIPLE - like the double sampled plan, but extended for a larger number of tests.

 

• the accept/retest/reject limits are set by statistical methods.

 

• Lot Sample Selection, must be as random as possible,

- use a random number generator,

- use a paper based method (e.g. pg. 288 in text)

 

• What to do when a lot is rejected