There is a 25 percent probability the economy will boom; otherwise, it will be normal. Stock Q is expected to return 18 percent in a boom and 9 percent otherwise. Stock R is expected to return 9 percent in a boom and 5 percent otherwise. What is the standard deviation of a portfolio that is invested 40 percent in Stock Q and 60 percent in Stock R? .7% 1.4% 2.6% 6.8% 8.1%