A travel website would like to estimate the difference between the average rental price of a car with automatic transmission versus the average rental price of a car with manual transmission at a certain airport. The table below shows the average one-week rental prices for two random samples, as well as the population standard deviations and sample sizes for each type of car. Complete parts a and b. Sample mean Sample size Population standard deviation Automatic $401.70 47 $20 Manual $363.90 35 $23 a. Construct a 90% confidence interval to estimate the difference in the average cost of a one-week rental between these two types of cars at the airport. Let the cars with automatic transmissions be population 1 and the cars with manual transmissions be population 2. The confidence interval is ($].$D). (Round to the nearest cent as needed.)