3. Suppose we have a data set with the following three observations, each of which appears as a pair (x,y): (x1 = 5;y1 = 2), (x2 = 3; y2 = -4), (x3 = 1; y3 = 5). Using the given data set, show that the summation of a product is not equal to the product of the individual summations. In other words, show that: * (**) (**) i=1 (Hint: show that the value of the expression on the left hand side is not equal to the value of the expression on the right hand side of the equation)