In a plant that makes ball bearings? samples are routinely subjected to a stringent crushing test. A sampling inspection scheme is required such that if out of a random simple of n bearings more than y fail the batch is rejected. Otherwise it is accepted. Denote by p the proportion of bearings in a large batch that will fail the test. It is required that there be a 95% chance of accepting a batch for- which p is a'i low as 0.3 and -a 95% chance of rejecting 3 batch for which pisas high as 0.5. Using the normal approximation, find values of n and y that will be satisfactory.