Ordinary least squares estimation is subject to heterogeneity bias if _____. 答案选项组 the regression model exhibits heteroskedastic
ty the unobserved effect is correlated with the observed explanatory variables the regression model includes a lagged dependent variable the explanatory variables do not change over time
The unobserved effect of heterogeneity is correlated with the observed explanatory variables. Population heterogeneity is bias in unobserved pre treatment factors which affect the outcome even without treatment.
