Newey-West bandwidth selection using Bartlett kernel   
   
   Cross-
Method Statistic Prob.** sections Obs
Null: Unit root (assumes common unit root process)     
Levin, Lin & Chu t* -1.88762  0.0295  29  224
Breitung t-stat -3.96624  0.0000  29  195
   
Null: Unit root (assumes individual unit root process)     
Im, Pesaran and Shin W-stat  -0.68013  0.2482  29  224
ADF - Fisher Chi-square  89.0099  0.0055  29  224
PP - Fisher Chi-square  138.488  0.0000  29  232
   
Null: No unit root (assumes common unit root process)     
Hadri Z-stat  4.00845  0.0000  29  261
   
** Probabilities for Fisher tests are computed using an asympotic Chi   
        -square distribution. All other tests assume asymptotic normality.

其余检验通过，但Im, Pesaran and Shin W-stat检验未通过，这种情况怎么处理呢。 可以确定不存在单位根吗？ 求助下大家