CHAPTER 12 Sections 12-1 10 223 553 223 5200.9 12352 X = X 553 12352 31729 1916.0 X = 43550.8 y 104736.8 171.055 ^ = 3.713 so y = 171.055+ 3.714x -1.126x ^ 1 2 -1.126 ^ y = 171.055+ 3.714(18)-1.126(43) = 189.49 Model 1 x 2 = 2 x 2 = 8 ^ y = 100 + 2x 1 + 8 ^ y = 108 + 2x 1 ^ y = 100 + 2x 1 + 4(8) ^ y = 132 + 2x 1 MODEL 1 Model 2 ^ y = 95+1.5x 1 + 3(2) + 4x 1 ^ y = 101+ 5.5x 1 ^ y = 95+1.5x 1 + 3(8) +16x 1 ^ y = 119 +17.5x 1 12-1. a) b) c) 12-3. a) 200 150 y = 132 + 2 y = 108 + 2 y 100 50 0 0 5 10 15 x MODEL 2 y = 119 + 17.5 x y 400 300 200 100 0 0 5 y = 101 + 5.5 x 10 15 x The interaction term in model 2 affects the slope of the regression equation. That is, it modifies the ^ amount of change per unit of x 1 on y . 12-1