highly significantp < 0.001
It could be observed that the coefficient of X 2 X 3 , X 1 2 , X 2 2 and X 3 2 were highly significant ( p < 0.001).
It could be observed that the coefficient of X 2 X 3 , X 1 2 , X 2 2 and X 3 2 were highly significant ( p < 0.001).