High-power experimental engines are being developed by the Stevens Motor Company for use in its new sports coupe. The engineers have calculated the maximum horsepower for the engine to be 540HP. Sixteen engines are randomly selected for horsepower testing. The sample has an average maximum HP of 550 with a standard deviation of 35HP. Assume the population is normally distributed. Step 1 of 2: Calculate a confidence interval for the average maximum HP for the experimental engine. Use a significance level of α=0.01. Round your answers to two decimal places.