1. Write down the single sampling plan from Z1.4 under the following situation: N=2000, Inspection Level II, General Inspection, Goal = 1% incoming quality level
Expert Answer
AQL=1%
Inspection level = General (level II)
Lot size = 2000
Step-1: First determine the Sample Size code letter
https://d2vlcm61l7u1fs.cloudfront.net/media%2F9c6%2F9c656a52-ff55-4db7-a516-b2742a89142f%2FphpxO9DLd.png
So, in this case, the code letter is ‘K’.
Step-2: Use the master table for single sampling normal inspection for letter K and AQL=1%
https://d2vlcm61l7u1fs.cloudfront.net/media%2F5e4%2F5e4a7a11-f6c1-42bc-8e09-8d77dcd974fe%2FphpuNM1ZT.png
So, the final sampling plan is –
Sample size = 125
Acceptance number = 3
Rejection number = 4
Note: tables are taken from ‘Introduction to Statistical Quality Control’ by DOUGLAS C. MONTGOMERY, John Wiley, 6th edition, pp. 657-658