A sporting goods company is testing two carriers to determine which company should deliver its packages.The company wants to test if Carrier 2 has faster shipping times.Packages were shipped to 36 locations using each of the carriers.The results are as follows:

Carrier 1: mean delivery time = 14 hours, s = 3.1 hours, n = 36

Carrier 2: mean delivery time = 13 hours, s = 2.6 hours, n = 36

Difference (Carrier 1 time - Carrier 2 time): mean = 1 hour, s = 2.9 hours, n = 36

The correct t-value for this question is: