Consider three stocks A, B and C costing $100 each. The annual returns on the three stocks have mean $5 and variance $10.
a. Suppose that the returns on the three stocks are i.i.d. Find the means and variance of the returns on Portfolio I, consisting of 3 units of A, and Portfolio II, consisting of 1 units each of A, B and C?
b. Suppose the returns from A and B have a correlation coefficient of -0.8 but they are uncorrelated with returns from C. Find the means and variances of the returns on the two portfolios.
c. Suppose the returns from A, B, and C are perfectly correlated (each pair have a correlation =1). Find the means and variances of the returns on the two portfolios. Is there any benefit to diversification in this case?