A special industrial battery must have a life of at least 400 hours. A hypothesis test is to be conducted with a 0.02 level of significance. If the batteries from a particular production run have an actual mean use life of383hours,the production manager wants a sampling procedure that only 10% of the time would show erroneously that the batch is acceptable. What sample size is recommended for the hypothesis test? Use35hoursas an estimate of the population standard deviation. (Round your answer up to the nearest integer.)