State: andrew plans to retire in 40 years. he plans to invest part of his retirement funds in stocks, so he seeks out information on past returns. he learns that from 1966 to 2015, the annual returns on s& p 500 had mean 11.0% and standard deviation 17.0% .plan: 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. we can use the central limit theorm to make an inference. solve: what is the probability, p1 , assuming that the past pattern of variation continues, that the mean annual return on common stocks over the next 40 years will exceed 10% ? (enter your answer rounded to two decimal places.)