(a) NAS Co. in a process of purchasing a stock. The company has gathered the following information about two possible stocks Y and Z. Stock Y Stock Z Probability Expected return Probability Expected return 11% 0.30 9% 0.30 18 0.45 18 0.45 22 0.25 25 0.25 You are required to help NAS Co. to make a decision, which stock is a better investment. (20 marks)