a) Suppose that we have two data points with (x,y) values (2,3) and (1,1). What is the sample correlation coefficient r for these two points? (You may figure this out by reasoning, use Splus, MATLAB, or hand calculate.) r = b) Now consider the two points (2,3) and (3,1). What is the sample correlation coefficient r for these two points? r = c) Now consider all three points (2,3), (1,1), and (3,1). What is the sample correlation coefficient r for these three points? r=