8. The 95 percent probability range of a normal distribution is defined as the mean plus or minus standard deviation(s). A. one B. three C. four D. two E. five 9. If you want to increase the potential annual return on your investments, you will need to: A. increase your portfolio's level of risk. B. increase your investment in bonds and lower your investment in stocks. C. reduce the standard deviation of your returns. D. increase your investment in U.S. Treasury bills and lower your investment in corporate bonds. E. reduce the expected variability of your returns