我是初学面板模型的菜鸟，得到如下这样的结果，请哪位人士给指导一下如何判断是否存在单位根，多谢！

Null Hypothesis: Unit root (individual unit root process)     
Series: Y1, Y2, Y3, Y4, Y5, Y6, Y7, Y8, Y9, Y10, Y11, Y12, Y13, Y14, Y15,   
        Y16, Y17, Y18, Y19, Y20, Y21, Y22, Y23, Y24, Y25, Y26, Y27, Y28, Y29,   
        Y30, Y31, Y32, Y33   
Date: 01/08/10   Time: 21:57   
Sample: 2001 2007   
Exogenous variables: Individual effects   
Automatic selection of maximum lags   
Automatic selection of lags based on SIC: 0 to 1   
Total number of observations: 185   
Cross-sections included: 33   
   
Method   Statistic Prob.**
ADF - Fisher Chi-square    137.235  0.0000
ADF - Choi Z-stat              -5.34351  0.0000