Regarding Nicholas Squeglia’s Zero Acceptance Number Sampling Plans, in the 4th edition for lot size 151-280 (1% AQL), a sample size of 20 is provided. However, in the 5th edition, for the same lot size 151-280 and AQL of 1%, the sample size is 29. Which is correct – a sample size of 20 or 29?
In the 5th edition of Nicolas Squeglia’s book, he mentions on page xii the rationale of the change in sample sizes. From the 5th edition, “in the early 2000’s, a large aerospace manufacturer was given permission by ASQ to reproduce the c=0 sampling table. They modified the table by changing several sample sizes, and for convenience it was therefore originally decided to carry those modifications into the fifth edition.”
Table 1a is the original tables (4th edition and previous) which has the sample size of 29. Use this table unless otherwise specified by contract.
Table 1b is the modified table which has a sample size of 20.
For more on this topic, please visit ASQ’s website.