4. Calculate the expected return and the volatility (standard deviation) of a portfolio consisting of Johnson & Johnson's and Walgreens' stocks using a wide range of portfolio weights in increments of 5% Plot the expected return as a function of the portfolio volatility. Correlation is 0.22. Using your graph, identify the range of Johnson & Johnson's portfolio weights that yield efficient combinations of the two stocks, rounded to the Johnson & Johnson Walgreen Company E[R] 7% 10% SD[R] 16% 20%