A Chicago-based firm has documents that must be quickly distributed to district offices throughout the U.S. The firm must decide between two delivery services, UPX (United Parcel Express) and INTEX (International Express), to transport its documents. In testing the delivery times of the two services, the firm sent two reports to a random sample of its district offices with one report carried by UPX and the other report carried by INTEX. Do the data on the next slide indicate a difference in mean delivery times for the two services? Use a .05 level of significance. [Hint: Perform a hypothesis test for difference for matched/paired samples, D = X1 X2] District Office UPX (X1) INTEX (X2) Seattle 32 25 Los Angeles 30 24 Boston 19 15 Cleveland 16 15 New York 15 13 Houston 18 15 Atlanta 14 15 St. Louis 10 8 Milwaukee 7 9 Denver 16 11

(a) State the hypothesis.

(b) Decide the significance level.

(c) Calculate the test statistic.