Derive the standard deviation of the returns on a portfolio that is invested in stocks x, y, and z, where twenty percent of the portfolio is invested in stock x and 35 percent is invested in Stock z. State of Economy Probability of State of Economy Rate of Return if State Occurs Stockx Stock y .09 08 - 24 .17 Boom Normal Recession 1.6.49 percent 7.72 percent Stock z .09 08 -.13 06 .02 5.65 percent 4.6.31 percent 5.7.38 percent Derive the standard deviation of the returns on a portfolio that is invested in stocks x, y, and z, where twenty percent of the portfolio is invested in stock x and 35 percent is invested in Stock z. State of Economy Probability of State of Economy Rate of Return if State Occurs Stockx Stock y .09 08 - 24 .17 Boom Normal Recession 1.6.49 percent 7.72 percent Stock z .09 08 -.13 06 .02 5.65 percent 4.6.31 percent 5.7.38 percent