Key Answers for Exercise 2: Q1: (1) Do not agree (DNA). When important regressors are omitted, OLS estimator becomes inconsistent. (2) DNA. As long as WIC hold and T is large, OLS is consistent and asymptotically normal. (3) DNA. Dropping regressors may c
ECON 725 2010 SPRING
KEY FOR SAMPLE EXAM
S.C. AHN
Q1. 1) A 2) DNA. If two random variables are normally distributed, then, zero correlation also means stochastic independence. 3) A. If X and Y are normal, the conditional mean of Y given X is linear in X:
ECON 725 2010 SPRING
SAMPLE EXAM 1
1 S.C. AHN
Q1. (40 pts.; 5 pts. on each.) Consider the following statements independently. State clearly whether you agree (A) or do not agree (DNA). If you do not agree, explain why not (2-3 line-long answers would be e
ECON 725 2010 SPRING
KEY FOR MID-TERM EXAM
S.C. AHN
Q1. 1) DNA. If y and x are jointly normal, then, projection = conditional mean. Also, if strong or weak ideal conditions are satisfied. 2) A 3) DNA. When t 1 , the regression using the corresponding vari
STUDY GUIDE (1) Coverage: Mostly on the topics covered after the mid-term exam. You would not have to study the coverage of the mid-term exam deeply, AS LONG AS YOU REMEMBER OLS FORMULAS, T-TESTS, AND F-TEST.
Major topics to study 1) WIC and nonlinear res
1. LINEAR REGRESSION UNDER IDEAL CONDITIONS (III) What do we learn in this section? [9] Weaker Assumptions. Does the OLS estimator have good properties under more realistic circumstances?
1 | Linear Regressions under Ideal Conditions (III)
[9] Nonnormal u
1. LINEAR REGRESSION UNDER IDEAL CONDITIONS (III) What do we learn in this section? [9] Weaker Assumptions. Does the OLS estimator have good properties under more realistic circumstances?
1 | Linear Regressions under Ideal Conditions (III)
[9] Nonnormal u
1. LINEAR REGRESSION UNDER IDEAL CONDITIONS (I) What do we learn in this section? [1] Regression model. What is regression model? [2] (Strong) Assumptions. What assumptions for regression models? How should a sample be collected from population? [3] Ordin
1. LINEAR REGRESSION UNDER IDEAL CONDITIONS (I) What do we learn in this section? [1] Regression model. What is regression model? [2] (Strong) Assumptions. What assumptions for regression models? How should a sample be collected from population? [3] Ordin
ECN 725 Spring 2010 Q1.
ASSIGNMENT 3 DUE April 16 (Friday), 2:00pm
S.C. AHN
(10 pts.) Consider a regression model y 1 2 x2 3 x3 u , which satisfies all SIC. Assume that regressors are stochastic. Let 2 be the OLS estimator of 2 from the regression of yt o
ECN 725
ASSIGNMENT 2 Due March 4 (Thursday)
Dr. AHN
1. (10 pts.) Suppose that E ( y | x1 , x2 ) 0 1 x1 x2 where x1 and x2 are stochastically independent and E ( x1 ) E ( x2 ) 0 . Show that Proj ( y |1, x1 , x2 ) depend on neither of x1 nor x2 . 2. (25 pts
ECN 725
ASSIGNMENT 1 DUE February 4 (Thursday)
S.C. AHN
Write your answers and derivation processes as clearly as possible. 1. (60 pts.) The joint probability distribution of X and Y is given by the following table: (For example, f(4,9) = 0.) x\y 2 4 6 (1
Q1. Suppose that E (u | x, v ) x v, E (u ) E (v ) 0 , E ( xu ) E ( xv ) 0 . Show that for some , E (u | x, v ) E (u | v ) v .
Q2. Let y 1 ( x1 , x2 ) u1 y 2 ( x1 ) u2
2 2 where var(u1 | x1 , x2 ) 12 and var(u2 | x1 ) 2 . Show that 12 2 .
Q3. Let y 1 2 x u
ECN 725 (LEC 15280) Econometrics I
SYLLABUS
Dr. S.C. (Min) Ahn Spring 2010
Unusual circumstances may result in the need to cancel a class. In such cases, this class will be OFFICIALLY CANCELED ONLY when the Department of Economics letterhead "CANCELED CLA
ECN 725
EXERCISE 2
S.C. Ahn
1. (25 pts; 5 pts. for each.) Comment on each of the following statements. No point will be given if no appropriate explanation follows. (Two or three-lines long answer would be sufficient for each question.) (1) (2) (3) (4) (5