Assume you don't know what statistics to use to estimate a population mean . You observe n observations of (yi) from a random sample of the population.

a) Set the OLS problem to estimate , find the first-order conditions and describe (in words), as precisely as possible, what is measured by OLS, the OLS estimator of . Show that you are indeed minimizing the sum of squared residuals, and not maximizing it.

b) What is the expected value of OLS? Show your work. c) What is the variance OLS? Show your work.

c) What is the variance OLS? Show your work.