1. Short Answer Questions Consider the following regression equation: Yl=or+3Xl+el_ (1} where i=1,2 ,...,n . Assume that the errors are Lid. 1. Suppose that you want to estimate :3 . Under what conditions does OLS yield an unbiased estimator of :9 ? 2. Describe conditions under which IV might be preferable to 0L8. Briefly justify your answer, and explain intuitively why the CILS estimate of ,8 might be biased. 3. What is the exclusion restriction? What happens if it is not met? What qualities does a good instrument have? 4 5. What is the relationship between IV and ZSLS? G 7 In ZSLS, can you have different controls in the two stages? . What are robust standard errors and why should one use them? Do Cullen and Jacob use them? 8. What is the Central Limit Theorem and why is it important? 9. Consider the supplemental lecture notes on \"Identifying Market Power'1 and the two lectures in which I discussed it (Lectures 13 and 14). In the model presented there, suppose that {13:0 . Can we then identify the degree of market power, A