A portfolio is invested 20 percent in stock A, 50 percent in stock B, and 30 percent in stock C. Assuming the returns are normally distributed, what is the 68 percent probability range of returns for any given year?
State of economy Probability Stock A Stock B Stock C
Boom 0.15 0.18 0.13 0.15
Normal 0.75 0.13 0.09 0.12
Reccesion 0.10 -0.25 0.02 -0.20