$(4)$ Use the file hw$2.$xls for this question. The file contains the expected excess

returns $E(r)-r_f$ for four stocks. The stocks are Wal Mart, Altria $($MO$),$

Anheuser$-$Busch $($BUD$),$ and Malibu Boats $($MBUU$).$ In addition, the file

contains the estimated variances and covariances of these four stock returns

for the last $60$ months.

$($a$)$ Find the minimum variance possible for a portfolio constructed using

these four stocks. What is the smallest variance?

$($b$)$ Repeat part a$)$ with no shorting allowed. What is the minimum variance

now?

$($c$)$ Find the tangency portfolio Sharpe Ratio with shorting allowed.

$($d$)$ Repeat part c$)$ with no shorting allowed. What is the maximum Sharpe

ratio now?

$($e$)$ Use the included range of Risk Premia to find the efficient frontier by

filling in cells A$23$ to A$31.$ Graph this efficient frontier in Excel, and make

the title of the graph state your name. Print the graph in a separate sheet

and include with your homework.