A statistics firm obtains a list of all cars in the U.S. that are registered with state DMV offices and randomly selects 81 cars from the list. For this sample, the average weight is found to be 2919 pounds with a standard deviation of 540 pounds. The weight of cars can be assumed to be normal. a) Calculate the 90% confidence interval for the parameter of interest and interpret it. b) Comment on the following interpretations for the confidence interval: i) 90% of all currently licensed registered vehicles weigh between 2819.1 and 3018.9 pounds. ii) The mean weight of all the currently registered vehicles is between 2819.1 and 3018.9 pounds 90% of the time.