Homework 1
Name: _Points:_/30
1. (10 points of paper grade) Prepare a title page for your paper. It should have the format
on the attached page.
2.
3.
4.
5.
6.
Homework Assignment
(2) For your airport, call your data, and plot passengers against the trend
EC421
Homework 5 - Solution
Gulcan Cil
HOMEWORK 5 - Solution
1- Structural equations model:
S = 1 + 2 A + uS
A = 1 + 2 S + uA
The researcher is interested in estimating the eect of advertising on sales, i.e. the rst equation. If he
ts the model using OLS,
Homework 4 - Key
(Due: In-class Wednesday, 11/05/2014)
Simultaneous Equations and Instrumental variables:
2. Suppose you were interested in the relationship between sales and advertising. Using a cross
section of 200 firms where sales depends only on adve
Homework 4
(Due: In-class Wednesday, 11/05/2014)
Name:
Paper Points:
/10
HW Points:
/30
1. (Paper, 10 points) In this homework you will work on the empirical model part of your airport
paper. This section follows from the conceptual model that identifies
STATAMANUAL
ECON421
September27,2013
by
WesleyW.Wilson
DepartmentofEconomics
UniversityofOregon
wwilson@uoregon.edu
LESSON1
LearningtoUseStata:RegressionandFigures
1.INTRODUCTION
STATA is a general purpose econometrics software and is widely used by appli
3. Which of the assumptions that are required for OLS to be BLUE is violated when the
error term is heteroskedastic? What are the consequences of estimating a heteroskedastic
model with OLS?
4. You need to test the following model for heteroskedasticity a
INTRODUCTION TO ECONOMETICS
Fall 2013
ECON 421
Instructor:
Office:
Office Hours:
Phone:
Email:
Wesley W. Wilson
PLC 470
MW 1:30-2:30, other times, by appointment. In general, I am around the
department and available for drop-in short questions.
(541) 346-
EC421
Homework 6 - Solutions
Gulcan Cil
HOMEWORK 6 - Solutions
1- a) See attached Stata output.
b) This implies the the coecient estimate we got for the test score variable, asvabc, suers from
measurement error bias and is inconsistent. Specically, it is
EC421
Homework 7 - Solutions
Gulcan Cil
HOMEWORK 7 - Solutions
1- a) See attached Stata output.
b) See attached Stata output for the results. As expected, the coecient estimate for 3 is positive
implying increases in income increases expenditures. It is s
EC421
Homework 8 - Solutions
Gulcan Cil
HOMEWORK 8 - Solutions
1- a) See attached Stata output.
b) Comparing the results, one can see that the in the dierenced equation, 2 is smaller, it is no longer
statistically signicant, and R2 is considerably lower.
EC421
Homework 4 - Solutions
Gulcan Cil
HOMEWORK 4 - Solutions
1- The true model: Stocks are a function of expected sales:
e
Yi = 1 + 2 Xi
But the investigator has data on actual sales, which dier from expected sales by u:
e
Xi = Xi + ui
So, the estimated
Homework 3
EC 421
Due: In class Wednesday 10/22/2014
Name:
Points:
/30
Paper:
/10
1. Paper: (10 Points) In this homework you will start working on the conceptual model
part of your airport paper. The idea is to develop an argument that helps explain the
c
EC421
Homework 1
Gulcan Cil
HOMEWORK 1 - Solutions
1- a) Average food quality rating: 21.12
Highest price: 91
See attached summary statistic table.
b) Yes, scatter plot indicates a positive relationship between service and price. See attached scatter plot
Economics 421/521
Winter 2006
Midterm 1
Answer each of the following questions (Problem 1 is worth 10 points, problems 2-7
are worth 15 points):
1. What is an unbiased estimator?
2. Suppose that the following model has been estimated using OLS:
1ny,= 210+
EC421
Homework 3
Gulcan Cil
HOMEWORK 3 - Due at the BEGINNING of lab on Week 5 (10/24-10/25)
1- In a certain industry, firms relate their stocks of finished goods, Y , to their expected annual sales, X e ,
according to a linear relationship
Yi = 1 + 2 Xie
CHAPTER 9: Serial Correlation
MODELLING SERIAL CORRELATION
Cov (ut ut - s ) =E (ut ut - s ) =0 for all t s
Serial Correlation: Violation of
Often observed in time series data, not in cross-section, but also in
panel data.
Hence, it is a rule rather than a
Term Project-Econ 421
Fall 2014
During this term, we will study the size of airports and changes in size over time. In the US, there are
nearly 20,000 airports. These include public airports that serve commercial airlines as well as airports
that are publ
Homework 7
(Optional)
Due in class on Wednesday, December 3, 2014
1. (2 points) What is autocorrelation?
2. (2 points) Name at least one cause of autocorrelation.
3. (4 points) Consider the following model:
a. Is autocorrelation a likely problem here? Why
HW7 Stata Output
2.5
2.55
2.6
2.65
2.7
1- a) logexp over time:
0
50
100
150
t
4.8
4.6
4.4
0
50
100
150
t
4.1
4.15
4.2
4.25
4.3
logInc over time:
4.05
log of price of gas
5
5.2
logP over time:
0
50
100
t
150
b)
. reg logexp
logp loginc
Source
SS
df
MS
Mode
Homework8
1a.RealGDP=5474.55+.0035259Passengers
RealGDP=74.3517+.0000879Passengers
Source
SS
df
MS
Model
Residual
34791731.1
8534301.55
1
45
34791731.1
189651.146
Total
43326032.6
46
Number of obs
F( 1,
45)
Prob > F
R-squared
Adj R-squared
Root MSE
941870
Assignment #4
Lujie Lou
For each part of this assignment, paste the code in a word document along with any graphs or
tables you estimate. Add any relevant discussion. Round answers to three decimal places when
appropriate. Report heteroskedastic-robust st
University of Oregon
Department of Economics
Due: In Lab Week of March 1
Professor Caroline Weber
Winter 2016
Assignment #6
Economics 421
Introduction to Econometrics
This data set was used in the analysis for Minimum Wages and Alcohol-Related Traffic Fat
10/15/12
EC 421
Last
I)
II)
III)
IV)
V)
Intro
Plims
Stochastic Regressors
A
B
C
Measurement Error
IV(Instrumental Variable)
Things needed to fix measurement error IVs
IV) Measurement Error:We have model we wish to estimate.
RHS variable is measured with e
10/10/12
EC 421
I)
II)
III)
IV)
V)
I)
Plims
Stochastic RHS
Measurement Error
Instrumental Variable
Review
Probability Limits: Some equation does not solve in expectation but collapse in probability.
Plim: Plim(X) = a
lim (|x | > ) = 0
= ny sufficiently l
EC421
3 - Stochastic Regressors
Gulcan Cil
Stochastic Regressors and Asymptotic Properties of OLS
What is stochastic regressors
Non-stochastic regressors are fixed, no random component to their value. The stochastic regressors, on the other hand, have a r
EC421
2 - Heteroscedasticity
Gulcan Cil
Heteroscedasticity
What is heteroscedasticity?
One of the assumption that we make in OLS is homoscedasticity, the variance of the error term
is the same for all observations: i2 = 2
Heteroscedasticity is the violati
EC421
1 - Introduction and Review
Gulcan Cil
Outline
1- Regression analysis
2- Ordinary Least Squares (OLS) Regression
OLS estimators
Assumptions of a model with non-stochastic regressors
Non-linear models and other transformations of variables
Interp
EC421
Homework 2
Gulcan Cil
HOMEWORK 2 - Due at the BEGINNING of lab on Week 3( 10/10-10/11)
Use Airports data set data set posted on Canvas to answer the following questions.
Data: Cross-sectional data: Top 100 airports in the U.S. during the 4th quarter