Following the Persian Gulf War, the Pentagon changed its logistics processes to be more corporate-like. The extravagant "just-in-case" mentality was replaced with "just-in-time7' systems. Emulating Federal Express and United Parcel Service, deliveries from factories to foxholes are now expedited using bar codes, laser cards, radio tags, and databases to track supplies. The table on the next page contains order-to-delivery times (in days) for a sample of shipments from the United States to the Persian Gulf in 1991 and a sample of shipments to Bosnia in 1995.

a. Use the SPSS printout on p. 384 to test whether the variances in order-to-delivery times for Persian Gulf and Bosnia shipments are equal. Use a = .05.

b. Given your answer to part

a, is it appropriate to construct a confidence interval for the difference between the mean order-to-delivery times? Explain.