Table 4 Regression indicators and analysis of variance (ANOVA) for the different models

p value

 X₁

4.79E−11

4.91E−11

0.04175

0.18523

 X₂

0.00017

1.60E−11

9.122E−5

1.090E−5

 X ²₁

0.38003

0.13104

0.26593

0.21956

 X ²₂

0.32261

0.78432

0.32293

0.73420

 X₁X₂

0.19371

0.96022

0.82280

0.19477

F value (model)

180.660

184.940

9.36420

14.3010

Significance F

1.82E−9

1.62E−9

0.00156

0.00028

F value (lack of fit)

0.89019

2.00101

0.68907

1.93724

R ²

0.98905

0.98930

0.82401

0.87731

\( {R^2}_{\text{adj}} \)

0.98358

0.98395

0.73601

0.81596