From time to time, one branch office of a company must make shipments to a certain branch office in another state. There are three package delivery services between the two cities where the branch offices are located. Since the price structures for the three delivery services are quite similar, the company wants to compare the delivery times. The company plans to make several different types of shipments to its branch office. To compare the carriers, each shipment will be sent in triplicate, one with each carrier. The results listed in the table are the delivery times in hours.

Shipment Carrier A Carrier B Carrier C

1 15.4 16.8 17.3

2 14.7 16.6 16.8

3 14.8 15.7 15.8

4 15.2 16.4 17.2

5 14.6 15.9 15.6

Is there evidence of a difference in mean delivery times among the three carriers?

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