For many years, the mean gas mileage on a long trip for a certain car was26.5miles per gallon. When a newly designed engine was incorporated into the car, the mean gas mileage appeared to change.In a random sample of15cars that have the new engine, the mean gas mileage was26.9miles per gallon with a standard deviation of0.55miles per gallon.At the0.05significance level, is there sufficient evidence to conclude that the mean miles per gallon of all cars with the new engine is greater than the prior average?We can assume that the population of miles per gallon values are normally distributed.

Which conclusion below is appropriate?

Group of answer choices