(a) Explain how one can secure statistical adequacy in practice by employing particular strategies in misspecification testing.

(b) Explain why in practice one should combine non-parametric (omnibus) with parametric directional M-S tests with a view to maximizing the breadth and length of the probing away from the statistical model being validated.

(c) Explain why rejecting the null using a less powerful M-S test provides better evidence for the presence of the departure than using a more powerful test.

(d) Explain intuitively the two auxiliary regressions used to test the statistical adequacy of the simple Normal model. Why do joint M-S tests have a distinct advantage over single assumption tests.