43. Customers at a fast-food restaurant buy both sandwiches and drinks. The following joint distribution summarizes the numbers of sandwiches (X) and drinks (Y) purchased by customers. i W W m: i: is drinkslo fins (3) Find the expected value and variance of the number of sandwiches. - (in) Find the expected value and variance of the number of drinks. o (c) Find the correlation between X and Y. (Hint: You might find the calculations easier if you use the alternative expression for the covariance shown in the Formulas section at the end of the chapter.) 0 d) Interpret the size of the correlation for the manager of the restaurant. 0 (e) If the profit earned from selling a sandwich is $1.50 and from a drink is $1.00, what is the expected value and standard deviation of the profit made from each Customer? - (f) Find the expected value of the ratio of drinks to sandwiches. Is it the same as ylx