17. Mary wants to buy stock in Vail and Guardian Insurance. The correlation coefficient for the two stocks returns is +0.40. If Mary invests 50% in Vail Resorts and 50% in Guardian Insurance, what is the standard deviation of her portfolio? a. 7.82% b. 11.1% c. 6.16% d. 9.63% 18. Which of the following statements is TRUE? a. Your best chance at reducing risk is to pick stocks that have a correlation coefficient equal to zero. b. Taking a stock's mean +/ - one standard deviation yields a 95% confidence interval. c. A coefficient of variation (CV) =5 implies more risk than 4CV=2 d. The probability distribution of completely certain retums (c.g. youlll cam 10% in the boom and 10% in the bust) is a horizontal line