The REG Procedure Model: MODEL1 Dependent Variable: v50_sq Analysis of Variance Sum of Mean Source DF Squares Square F Value Pr > F Model 5 3737.17015 747.43403 502.86 <.0001 Error 19 28.24122 1.48638 Corrected Total 24 3765.41137 Root MSE 1.21917 R-Square 0.9925 Dependent Mean 23.92935 Adj R-Sq 0.9905 Coeff Var 5.09488 Parameter Estimates Parameter Standard Variable DF Estimate Error t Value Pr > |t| Intercept 1 3.64332 0.83615 4.36 0.0003 layers 1 0.85469 0.03372 25.35 <.0001 sharp 1 0.76866 1.18249 0.65 0.5235 fsp 1 0.49887 1.13634 0.44 0.6656 layers_sharp 1 0.14962 0.04768 3.14 0.0054 layers_fsp 1 0.13697 0.04670 2.93 0.0085 The REG Procedure Model: MODEL2 Dependent Variable: v50_sq Analysis of Variance Sum of Mean Source DF Squares Square F Value Pr > F Model 3 3718.97341 1239.65780 560.59 <.0001 Error 21 46.43796 2.21133 Corrected Total 24 3765.41137 Root MSE 1.48705 R-Square 0.9877 Dependent Mean 23.92935 Adj R-Sq 0.9859 Coeff Var 6.21435 Parameter Estimates Parameter Standard Variable DF Estimate Error t Value Pr > |t| Intercept 1 1.58799 0.72365 2.19 0.0396 layers 1 0.95141 0.02340 40.66 <.0001 sharp 1 3.94817 0.74353 5.31 <.0001 fsp 1 3.36806 0.72298 4.66 0.0001 The REG Procedure Model: MODEL3 Dependent Variable: v50_sq Analysis of Variance Sum of Mean Source DF Squares Square F Value Pr > F Model 1 3645.44546 3645.44546 698.91 <.0001 Error 23 119.96591 5.21591 Corrected Total 24 3765.41137 Root MSE 2.28384 R-Square 0.9681 Dependent Mean 23.92935 Adj R-Sq 0.9668 Coeff Var 9.54408 Parameter Estimates Parameter Standard Variable DF Estimate Error t Value Pr > |t| Intercept 1 4.10651 0.87799 4.68 0.0001 layers 1 0.94937 0.03591 26.44 <.0001