Risk Premiums. Refer to Table 1.1 for large-stock and T-bill returns for the period 1973-1977:

a. Calculate the observed risk premium in each year for the common stocks.

b. Calculate the average returns and the average risk premium over this period.

c. Calculate the standard deviation of returns and the standard deviation of the risk premium.

d. Is it possible that the observed risk premium can be negative? Explain how this can happen and what it means.

Year	Common Stock	U.S. Treasury Bills
1973	-14.69	7.29
1974	-26.47	7.99
1975	37.23	5.87
1976	23.93	5.07
1977	-7.16	5.45