4) Johnson & Johnson and Walgreen Company have a correlation of 16% and expected returns and standard deviations as shown below. E(r) o Johnson & Johnson 8% 17% Walgreen Company 11% 21% a) Calculate the expected return and volatility of a portfolio that is equally invested in the two stocks that consists of a long position of $12,000 in Johnson & Johnson and a short position of $4,000 in Walgreen. b) Calculate the expected return and volatility of a portfolio of Johnson & Johnson and Walgreen using a wide range of portfolio weights. Plot the expected return as a function of the portfolio volatility. Using your graph, identify the range of portfolio weights that yield efficient combinations of the two stocks rounded to the nearest percentage point