Assume for securities x, Y. and Z are as shown here. a. Calculate the change in return for each security if the market experiences an increase in its rate of return of 15% over the next period. b. Calculate the change in return for each security if the market experiences a decrease in its rate of return of 10% over the next period. c. Which stock is risky in economic downturn? Which stock will gain when the economy is very good? Which stock will you consider given both good and bad times of the economy? (d) Referring to question no 3 above, assume you have a fund of $9,000, invested $3000 in X, $2000 in Y and the rest is in Z. Calculate the Portfolio Risk