historical data showing that the average annual rate of return on the SAP 500 portfolio over the past 80 years has averaged roughly 8% more than Treasury bill retum,nd hat the S&P 500 standard deviation has been about 20% per year. Assume these values are representative of investors' expectations for future performance and that the current T-bill rate is 5%. Calculate the expected returnm and variance of portfolios invested in T-bills and the S&P 500inde with weights as follows: (10 points) Wells 0.2 0.4 0.8 1.0 1.0 0.8 0.6 0.2 characteristics of stocks 4 and B are given as follows: are many stocks in the security market and that the that it is possible to borro ossible to borrow at the risk-free rate., rs What mus Suppose uasst Think about constructing a risk-free portfolio from stocks Ad int : Think about constructing a risk-free portfolio from -1, risk-free ra (10 points) stocks A and of the