extremely significantp < 0.001
The results of calculating the p-value show that: p 0.05, the difference is not significant (ns); 0.01p 0.05, the difference is significant (*); and 0.001p 0.01, the difference is extremely significant, the difference is very significant (**); 0.0001 < p < 0.001, the difference is extremely significant (***). 3.