The F-value of 19.96 suggests that the model is significant, where this large F-value might occur due to noise of 0.01% of the time. p-values less than 0.0500 indicate that the model terms, i.e., the model terms Vc, Dc, Vc, Fz, and Vc2 are significant. On the other hand, values over 0.1000 suggest that the model terms are not significant. Model reduction may help for a model with many insignificant terms (except those necessary to enable hierarchy).
The F-value of 0.2783 for the lack of fit suggests that it is minimal compared to the pure error. A substantial lack of fit F-value may occur 95.96% of the time due to noise, and a non-significant lack of fit is preferred. The following Design-Expert software’s (StatEase, Minneapolis, MN, USA) regression equation of the objective factors was obtained upon running the regression.