1. The lifetime of a disk drive head is normally distributed with a population mean of 1000 hours and a standard deviation of 120 hours. Determine the probability that the average lifetime for 16 disk drives will exceed 940 hours
2. Suppose that 40 percent of the voters in a particular region support a candidate. Find the probability that a sample of 900 voters would yield a sample proportion in favor of the candidate within 3 percentage points of the actual proportion