Our starting place is the first order seasonal autoregressive model. Its series are shown to have canonical model-based decompositions whose finite-sample estimates, filters, and error covariances have simple revealing formulas from basic linear regression.We obtain analogous formulas for...

In his somewhat informal derivation, Akaike (in "Proceedings of the 2nd International Symposium Information Theory" (C. B. Petrov and F. Csaki, Eds.), pp. 610-624, Academici Kiado, Budapest, 1973) obtained AIC's parameter-count adjustment to the log-likelihood as a bias correction: it yields an...