Chapter 5.7, Problem 6E

A sample of 10 diesel trucks were run both hot and cold to estimate the difference in fuel economy. The results, in mpg, are presented in the following table. (From “In-use Emissions from Heavy-Duty Diesel Vehicles,” J. Yanowitz, Ph.D. thesis, Colorado School of Mines, 2001.)

Truck	Hot	Cold
1	4.56	4.26
2	4.46	4.08
3	6.49	5.83
4	5.37	4.96
5	6.25	5.87
6	5.90	5.32
7	4.12	3.92
8	3.85	3.69
9	4.15	3.74
10	4.69	4.19

Find a 98% confidence interval for the difference in mean fuel mileage between hot and cold engines.