2. Test for autocorrelation when a lagged dependent variable serves as an independent variable Suppose that Y=a+ Bra+rX,+E Durbin h statistic(T is the observation No T h= N(O,1) 1-Tvar(β) d T h=(1 T var(B2. Test for autocorrelation when a lagged dependent variable serves as an independent variable Suppose that Durbin h statistic (T is the observation No.) Y Y X t t t t = + + +     −1 ˆ (0,1) ˆ 1 var( ) T h N T   = − (1 ) 2 ˆ 1 var( ) d T h T  = − −