The historical returns on a portfolio had an average return of 6% and a standard deviation of 4%. Assume returns on the portfolio follow a bell-shaped distribution. Use the empirical rule to answer the following questions. a. What percentage of returns were between 2 percent and 10 percent? Percentage of returns b. What percentage of returns were greater than 10 percent? Percentage of returns % c. What percentage of returns were below -2 percent? Percentage of returns %