谢谢!
可是,还是不明白,那应该选择什么样的模型呢?如果选了fe,就什么也解释不了了。
做hausman的时候,揭示说:the rank of the differenced variance matrix (1) does not equal the number of coefficients
being tested (3); be sure this is what you expect, or there may be problems computing the
test. Examine the output of your estimators for anything unexpected and possibly consider
scaling your variables so that the coefficients are on a similar scale.
不知道是否有关系?