i need help with #4 pls!

rate 2. What effect would diversifying your portfolio have on returns and the level of risk you incurr? 3. Compare and contrast systematic and unsystematic risk. 4. Based on the information below, which investment is better based on the risk and return of each. Why? Be sure to calculate standard deviation and return on each. (Hint: look at pages 204-205) Please work out the chart and show your work. Common Stock A Probability Return 0.3 11% 0.4 15% 0.3 19% Common Stock B Probability Return 0.2 -5% 0.3 696 0.3 14% 0.2 22% 5. (A) Define holding period returns. (B) From the price data below, compute the holding-period returns for periods 2 through 4