Ordinary least squares estimation is subject to heterogeneity bias if _____. 答案选项组 the regression model exhibits heteroskedasticty 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

Respuesta :

Answer:

Unobserved effect.

Step-by-step explanation:

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.