Andrew plans to retire in 50 years. He plans to invest part of his retirement funds in stocks, so he seeks out information on past returns. He learns that over the years, the annual returns on U. S. common stocks had mean 13.9% and standard deviation 17.0%. The distribution of annual returns on common stocks is roughly symmetric, so the mean return over even a moderate number of years is close to Normal. (Round your answers to four decimal places.)