*MacKinnon (1996) one-sided p-values. Augmented Dickey-Fuller Test Equation Dependent Variable: D(VNINDEX,2) Method: Least Squares Date: 04/16/10 Time: 12:02 Sample (adjusted): 1/20/2010 4/15/2010 Vì prob*= sai phân bậc 1 của chuỗi dừng. Ta có sơ đồ Line- sympol: