Stationarity(v) Three basic box-Jenkins models for a stationary time series ty (3) Autoregressive-moving average model of order p and g (arma(p, q) y=+y1+n2y2+…+yp +6-661-62E12-…-6 g t-g i.e., y, depends on its p previous values and g previous random error terms9 Stationarity (V)  Three basic Box-Jenkins models for a stationary time series {yt } : (3) Autoregressive-moving average model of order p and q (ARMA(p,q)) i.e., yt depends on its p previous values and q previous random error terms , 1 1 2 2 1 1 2 2 t t t q t q t t t p t p y y y y − − − − − − + − − − − = + + + + e  e  e  e      