One year bond yield is 3 percent, two year bond yield is 4 percent, three year bond yield is 5 percent

The returns on the common stock of maynard cosmetic specialties are quite cyclical. in a boom economy, the stock is expected to return 22 percent in comparison to 9 percent in a normal economy and a negative 14 percent in a recessionary period. the probability of a recession is 35 percent while the probability of a boom is 10 percent. what is the standard deviation of the returns on this stock?