1) Explain what an estimator is. Illustrate using an example.

2) What is an estimate?

3) Explain the relationship represented by the sample regression function.

4) Explain the difference between the sample and population regression functions.

5) Explain the meaning of the conditional mean of the dependent variable in the population regression function. Illustrate using an example.

6) Explain the meaning of the fitted value in the sample regression function. Illustrate using an example.

7) Explain the difference between the explained sum of squares and the residual sum of squares.

8) What is the difference between a cross section and pooled cross section?