Anyone out there who enjoys semi-complicated statistics problems, please help! Haven't taken any stat courses since my into stat class and this econometrics problem has me stumped.

Question

anonymous · Answer

$1 in a stock yeilds Rs, $1 in a bond yeilds Rb 

Rs is random with a mean .08 and SD of .07 

Rb is random with a mean .05 and SD of .04 

Correlation of Rs and Rb is .25 

If you place a fraction w of your money in the stock fund and the rest, 1-w, in the bond fund, then your return on you investment is 

R=wRs+(1-w)Rb 

A. Suppose that w=.5 Compute the mean and SD of R.?? 
B Suppose that w=.75 Compute the mean and SD of R.?? 
C What value of w makes the mean of R as large as possible? What is the SD of R for this value of w? 
D. What us the value of w that minimizes the SD of R??