An engine additive is being tested to see whether it can effectively increase gas mileage for a number of vehicles. Twenty assorted vehicles had their gas mileage, in miles per gallon, measured. Then, the engine additive was placed into each of the engines, and the gas mileage was measured again. Let µA be the mean gas mileage of the vehicles without the engine additive, and let µB be the mean gas mileage of the vehicles with the engine additive. The 99% confidence interval for the true mean difference between the two means is (2 mpg, 5 mpg). Which of the following statements is the best interpretation of this confidence interval?
With probability 0.99, the interval (2 , 5) contains the true difference µB- µA
µB is approximately equal to 5 mpg, and µA is approximately equal to 2 mpg.
µB- µA is approximately equal to 3.
µB- µA with probability 0.99
It is likely that the difference µB- µA will exceed 5.