求助坛友，理论上分析可能存在内生性，使用解释变量的滞后一期作为 工具变量，结果Hausman 检验p值为0.98（看陈强老师的书说存在异方差是hausman检验结果不准确），所以又做了GMM，系统GMM结果如下：
Arellano-Bond test for AR(1) in first differences: z =   1.55  Pr > z =  0.121
Arellano-Bond test for AR(2) in first differences: z =   0.33  Pr > z =  0.745
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Sargan test of overid. restrictions: chi2(34)   = 693.09  Prob > chi2 =  0.000
  (Not robust, but not weakened by many instruments.)
Hansen test of overid. restrictions: chi2(34)   =  25.08  Prob > chi2 =  0.867
  (Robust, but weakened by many instruments.)

Difference-in-Hansen tests of exogeneity of instrument subsets:
  GMM instruments for levels
    Hansen test excluding group:     chi2(27)   =  23.95  Prob > chi2 =  0.633
    Difference (null H = exogenous): chi2(7)    =   1.13  Prob > chi2 =  0.992
  iv(open FDI K Edu Govn Fin)
    Hansen test excluding group:     chi2(28)   =  27.75  Prob > chi2 =  0.478
    Difference (null H = exogenous): chi2(6)    =  -2.67  Prob > chi2 =  1.000

请问这个结果怎么看啊，这是指不存在内生性问题吗？