Answer:
portfolio's standard deviation = 0.3256
Step-by-step explanation:
Stock Expected Return Standard Deviation Wi
A 10% 30% 0.2
B 20% 40% 0.8
covariance = [(10% - 10%) x (20% - 20%)] / (2 - 1) = 0
portfolio's standard deviation = (stock A's Wi² x variance) + (stock B's Wi² x variance) + (2 x covariance x weight A x weight B)
portfolio's standard deviation = √{(0.2² x 0.09) + (0.8² x 0.16) + 0} = √(0.0036 + 0.1024) = √0.106 = 0.3256