A consumer group studied two different manufacturers of cars, j and k, to investigate differences in gas mileage for cars made by the two manufacturers. For a similar type of car, a random sample of 15 cars from j and a random sample of 12 cars from k were selected, and the gas mileages, in miles per gallon (mpg), were recorded. The difference in the sample mean gas mileages was used to construct the 90 percent confidence interval (3. 5,5. 7). Assuming all conditions for inference were met, which of the following is a correct interpretation of the interval?