In what follows, you have two observations on each of n individuals. The observations are (x1,y1), (x2, y2), . . ., (xn, Yn). Define x and y as usual, 2, and the denominator, and the correlation as usual with n in the denominator, s and as usual with n - 1 in 1 n - (*) (*) r = = Notice the change in notation: everything defined in this paragraph pertains to lists of numbers, not random variables. Problem 9E: Some texts definer as follows: n 1 - r = - (*) (*) n-1 i=1 Sy Show that the two definitions are equivalent. This form is hard to use in derivations. I recommend that you stick to the original form of the definition.