extremely significantP ≤ 0.05
The P-value reflects the regression effect of the parameter 53 – 55 , P < 0.0001 means the regression effect of the factor is extremely significant, 0.0001 ≤ P ≤ 0.05 means the regression effect of the factor is significant, and P ≥ 0.05 means the regression effect of the factor is insignificant 56 – 58 .