What is a reasonable rational for selection of sample size?
The selection of sample size is a difficult question, as it depends upon the level of risk associated with the process. If the process of making a package causes many defects in itself, and the process cannot be refined to reduce the defects, then the sample size may need to be higher. Likewise, if the result of a defect causes significant harm to a patient, then more testing will be required to ensure that the defect is found before it can cause harm. For packaging, the process can usually be refined by compliance to standards like ISO 11607 to produce packages that have a high probability of withstanding the hazards and reaching their destination without failure. If the failure is obvious, the product will not be used. If the failure is a pinhole and undetected, the risk of a microbe entering the package and contaminating the product is also probably small. So, testing packages for seal failure using bubble leak testing with a sample size of 30 is probably a reasonable risk consideri
