For threaded studs, how many specimens must pass?

• A. 4 studs
• B. 5 studs
• C. 6 studs
• D. 7 studs

Answer: (B)

Testing threaded studs uses a fixed sampling plan to decide if a batch is acceptable. Seven specimens are evaluated, and the lot is accepted only if at least five of them pass. This setup allows up to two failures to be tolerated, recognizing some variability while still ensuring the overall quality is adequate. If four or fewer pass, the batch doesn’t meet the standard and must be rejected or retested. So the minimum passing number is five.