A Proof! Show that in a single variable regression, R = PX,Y where px,y is the sample correlation of X and Y. As a reminder, (X-X)(Y-Y) '(x, -x)2 VE (. - Y)2 px,y = Hint: This is just chugging through formulas you already have. Start with the definition of R ESS/TSS and then plug in for , Bo and B1.