Function of variable). The demand for a certain product of Vulcan Co. in New Orleans varies greatly from month to month. The probability distribution in the following table, based on the past two years of data, shows the company's monthly demand: (8 points) Unit demand (items), X 100 200 300 400 Total Probability, P[X] 0.1 0.3 0.5 0.1 1.0 (a) Find the expected value of the monthly demand X. (b) What is the standard deviation of the monthly demand X? (c) Suppose that the total revenue is expressed as Y = 10 X - 400. Find the expected value of Y. (d) What is the standard deviation of the total revenue Y