You decide to invest in a portfolio consisting of 15 percent Stock X, 51 percent Stock Y. and the remainder in Stock Z. Based on the following information, what is the standard deviation of your portfolio? State of Economy Normal Probability of State of Economy .77 .23 Return if State Occurs Stock x Stock Y Stock Z 10.508 3.90% 12.908 17.80% 25.808 17.30% Boom Multiple Choice 2.51% 3.35% 8.44% 7.24% 5.79%