It can be seen from Table 5 that the quadratic model, which has a high Fischer ratio and a p value lower than 0.0001, indicated that the model was statistically significant. The model determination coefficient (R2) was 0.9921, indicating that the model could explain 99.21% of the variable data. RAdj 2 was 0.9814, further indicating that the model has a high degree of fitting. The CV% (coefficient of variation) of 3.68 was very low, illustrating that