Question: In class we solved a problem comparing gasoline driven and electric mail trucks. The manufacturer of the electric trucks hve since announced a new battery that leaves the cost of operating them about the same, but have made the variance smaller. They are able to supply 50 new trucks for a trial period at the US Postal Service, who replicates the test we did in class. The 200 gasoline driven trucks were associated with an average cost of 6.70 cents per mile and a variance of 0.36. The 50 electric trucks were associated with an average cost of 6.53 cents per mile and a variance of 0.32. If we keep a at 0.05, is there a difference between the types of trucks? In class I took a shortcut solving the problem with a z-score. Solve it more properly here utilizing a t-test.