1. Assume the above standard deviation is the population standard deviation. Calculate the probability that a 30-day T-bill will earn a monthly return of 0 percent or less. Assume fund returns are normally distributed.

2. Assume the above standard deviation is the population standard deviation. Calculate the probability that a 30-day T-bill will earn a monthly return of 0 percent or more. Assume fund returns are normally distributed.

TABLE 25 Exchange Traded Fund and US 30 Day T-Bill Mean Return and Standard Deviation of Return, 2003-2012 Fund/T-Bill Arithmetic Mean (%) Standard Deviation of Return (%) IWM 9.26 22.36 SPY 6.77 19.99 30 day T-bill 1.58 1.78 Sources: finance.yahoo.com and www.federalreserve.gov