An independent group of food service personnel conducted a survey on tipping practices in a large metropolitan area. They collected information on the percentage of the bill left as a tip for20 randomly selected bills. The average tip was13.6% of the bill with a standard deviation of 2.4%. Assume that the tips are approximately normally distributed. Construct an interval to estimate the true average tip (as a percent of the bill) with95% confidence. Round the endpoints to two decimal places, if necessary.