Pool unit root test: Summary     
Series: LOGGDPHZ, LOGGDPCD, LOGGDPHEB, LOGGDPGZ,    
        LOGGDPCQ, LOGGDPNJ, LOGGDPSH, LOGGDPNN, LOGGDPTJ,    
        LOGGDPWH, LOGGDPBJ, LOGGDPSY, LOGGDPFZ, LOGGDPSZ,    
        LOGGDPWLMQ, LOGGDPHF, LOGGDPJN, LOGGDPXA    
Date: 08/02/08   Time: 19:56    
Sample: 1990 2007    
Exogenous variables: Individual effects, individual linear trends    
Automatic selection of maximum lags    
Automatic selection of lags based on SIC: 0 to 3    
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* -5.97380                                 0.0000  18  263
Breitung t-stat -2.45875                                        0.0070  18  245
    
Null: Unit root (assumes individual unit root process)     
Im, Pesaran and Shin W-stat   -7.96963              0.0000  18  263
ADF - Fisher Chi-square  141.408                     0.0000  18  263
PP - Fisher Chi-square  11.2064                       1.0000  18  302
    
** Probabilities for Fisher tests are computed using an asymptotic Chi    
        -square distribution. All other tests assume asymptotic normality.    
我这是用gdp的自然对数的数据作单位根检验，经过画图发现 存在趋势项和截距项 ，结果得出这样结论  其他几个都拒绝原假设认为是平稳序列，而PP则接受原假设，那么这到底是平稳的还是非平稳的？