∑ X, or the sum of all the X values, is 31.4. ∑Y, or the sum of all the Y values, is 29.3. ∑ X 2, or the sum of each X value squared, is 102.5. ∑ Y 2, or the sum of each Y value squared, is 89.99. ∑ XY, or the sum of the products of X and Y, is 94.75. Formula 16.2 is used to compute the slope of the regression line (b in the equation for a straight line): (16.2)
