A statistics firm obtains a list of all cars in the US. 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. a. Calculate the 90% confidence interval for the average weights of all currently licensed cars, and interpret the interval in the context of this problem. What conditions or assumptions did you assume in constructing this interval