Table 2. Analysis of variance for the second-order model on Y1

Source DF Sum of squares Mean square F-value Pr>F-value
Model 14 2,152.7838 153.7703 3.24 0.0240
Error 12 568.9725 47.4144
Lack of fit 10 563.8458 56.3846 22 0.0442
Pure error 2 5.1267 2.5633
Corrected total 26 2,721.7563
Root MSE=6.8858, Dependent mean=79.3296, r2=0.7910, Adj r2=0.5471
Model terms: X1, X2, X3, X4; X12, X22, X32, X42; X1X2, X1X3, X1X4, X2X3, X2X4, X3X4.