highly significantp < 0.001
The coefficients of X 3 , X 1 X 2 , X 2 X 3 , X 1 2 , X 2 2 , and X 3 2 were highly significant ( p < 0.001), while those of X 1 and X 2 were statistically significant ( p < 0.01).
The coefficients of X 3 , X 1 X 2 , X 2 X 3 , X 1 2 , X 2 2 , and X 3 2 were highly significant ( p < 0.001), while those of X 1 and X 2 were statistically significant ( p < 0.01).