Regressors

Fiexed Regressors

Variance Positive
A special case of the next one.

No Exact Multicollinearity

[sim] show effects of V(x). [sim] show effects of V(e).

Estimation
Least Squares
Maximum Likelihood
Instrumental Variables

Conclusions
Expectation
Variance

Dummy Variables & Subsamples

Pitfalls

Why is using race (or marital status) as a regressor a really bad idea?
What is wrong with highest grade attained (or years in school) as a measure of education?
Should I worry about really small, but significant coefficients?