A stock had returns of 8 percent, -6 percent, 4 percent, and 14 percent over the past four years. What is the standard deviation of these returns? If the economy booms, RTF, Inc. stock is expected to return 11 percent. If the economy goes into a recessionary period, then RTF is expected to only return 4 percent. The probability of a boom is 62 percent while the probability of a recession is 38 percent. What is the variance of the returns on RTF, Inc. stock