Problem #2: Arithmetic Average Returns & Standard Deviations Using the data from the previous problem, answer the following questions. Show work and keystrokes. a. What was the arithmetic average return of the S&P500 for the 10-year period? b. What was the standard deviation of returns for the 10-year period? c. What was the variance of returns for the 10-year period? d. Using this data, and assuming that returns are normally distributed, what range of stock returns would you expect 68% of the time for a given year?