Fuel efficiency of manual and automatic cars, Part I:Each year the US Environmental Protection Agency (EPA) releases fuel economy data on cars manufactured in that year. Below are summary statistics on fuel efficiency (in miles/gallon) from random samples of cars with manual and automatic transmissions manufactured in 2012. Do these data provide strong evidence of a difference between the average fuel efficiency of cars with manual and automatic transmissions in terms of their average city mileage? Assume that conditions for inference are satisfied.

City MPG, Automatic City MPG, Manual

Mean 16.12 19.85

SD 3.58 4.51

n 26 26

Hypotheses for this test are:

Ho:____________

Ha:______________

The test statistic to two decimal is: _____________

The p-value to FOUR decimal using (n1-1)+(n2-1) is: _______________

_The data evidence supports no difference in efficiency.

_The data evidence supports there is a difference in efficiency.

_The data is not provide sufficient evidence of a difference.