Using the Single-Index Model, a security analyst has obtained the following estimates for stock A and stock B:

stock	alpha	beta	firm-specific standard deviation
A	3.8%	0.8	30%
B	4.2%	1.2	40%

The analyst also estimates that the market portfolio has an expected return of 10% and a standard deviation of 22%. The risk-free rate is 6%.

Suppose that we construct a portfolio W with 70% of proportion in stock A and 30% of proportion in stock B. Compute the following of portfolio W:

a) the excess return,

b) beta,

c) the firm-specific standard deviation,

d) the standard deviation.