On consecutive Sundays, Mac, the owner of a local newsstand, purchases a number of copies of The Computer Journal, a popular weekly magazine. He pays 25 cents for each company and sells each for 75 cents. Copies he has not sold during the week can be returned to his supplier for 10 cents each. The supplier is able to salvage the paper for printing future issues. Mac has kept careful records of the demand each week for the Journal. (This includes the number of copies actually sold plus the number of customer requests that could not be satisfied). The observed demands during each of the last 52 weeks were: 15 14 18981 13 91 1197 19 11 11 12 11 12 965 2E 12 11 HELPE 12 11 4 15 alcol 18 9 9 4 15 15 28797 22 18 17 19 17 4 10 000 18 9 19 a 7 0 14 10 14 14 15 9 16 18 14 LLahtlm. 0 2 4 6 8 10 12 14 Number of sales 20 22 118 HESTE 11 12 16 17 Figure. Frequency histogram for a 52-week history of sales Mac wishes to determine the number of copies of The Computer Journal he should purchase each Sunday. Historical data showed that the demand during any week is a random variable that is approximately normally distributed with mean 11.73 and standard deviation 4.74. Each copy is purchased for 25 cents and sold for 75 cents, and he is paid 10 cents for each unsold copy by his supplier.