This is further proved that the more return is apparently generated by price manipulation rather than the corporation real value through the dumb variable analysis. 通过操纵哑变量的引入,进一步证明了这些股票表现出来的较高收益率是操纵而非基本面改善的结果。
This paper tries to associate dumb variable with multilevel model to study non-response errors. Meanwhile, this paper uses other methods. 本文还尝试应用虚拟变量和多阶模型结合的方法研究出现无回答时的估计问题。同时,本文还采用了其它研究方法。