Traffic speed: The mean speed for a sample of 43 cars at a certain intersection was 28.72 kilometers per hour with a standard deviation of 2.49 kilometers per hour, and the mean speed for a sample of 134 motorcycles was 34.17 kilometers per hour with a standard deviation of 3.72 kilometers per hour. Construct a 99% confidence interval for the difference between the mean speeds of motorcycles and cars at this intersection. Let J denote the mean speed of motorcycles and round the answers to at least two decimal places. A 99% confidence interval for the difference between the mean speeds, in kilometers per hour, of motorcycles and cars at this intersection is