Each year the US Environ- mental 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.

a)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. Conduct a hypothesis test with all steps clearly demonstrated. What are your hypotheses? What is the p-value? What is your conclusion?

b)Showing all steps, compute a 95% confidence interval for the related parameters. Using this CI you just constructed, is there a significant difference between the average fuel efficiency of cars with manual versus automatic transmissions in terms of their average city mileage? Why?

\f