An estimate of the percentage defective in a lot of pins supplied by a vendor is desired to within 1% with a 90% confidence level. The actual percentage defective is guessed to be 4%.

a. What is the minimum sample size?

b. If the actual percentage defective may be anywhere between 3% and 6%, tabulate the minimum sample size required for actual percentage defective from 3% to 6%.

c. If the cost of sampling and testing n pins is (25 + 6n) dollars, tabulate the costs for the same percentage defective range as in part (b).