Returns and the Bell Curve
An investment has an expected return of 8 percent per year with a standard deviation of 4 percent. Assuming that the returns on this investment are at least roughly normally distributed, how frequently do you expect to lose money?

Using Returns Distributions
Based on the historical record, if you invest in long- term U. S. Treasury bonds, what is the approximate probability that your return will be less than 6.0 percent in a given year? What range of returns would you expect to see 95 percent of the time? 99 percent of the time?