Econ 2123. Introduction to Econometrics
Section 83. Prof. Williams
Homework 1
Solutions
1.
In each of the following examples is the assumption of a random sample reasonable?
Why or why not?
i. Time series: X1 , X2 , . . . , Xn where X1 represents the US u
Econ 2123. Introduction to Econometrics
Sections 80/83. Prof. Williams
Homework 2
Solutions
1.
1
Recall the sample standard deviation estimator, s = n1 n (Xi X)2 . Is this
i=1
estimator consistent if X1 , X2 , . . . , Xn is a random sample? Explain why. M
Econ 2123. Introduction to Econometrics
Sections 80/83. Prof. Williams
Homework 3
Solutions
1. Law of iterated expectations
Suppose Rt is the rate of return on an investment in period t. Rt is a random variable
because it is uncertain until period t + 1.
Econ 2123. Introduction to Econometrics
Sections 80/83. Prof. Williams
Homework 4
Solutions
1.
Suppose that a random sample of 200 40-year old men is selected from a population
and that these mens annual income is recorded. Suppose I am also able to obtai
ECON 123 (TROST) QUIZ 1 SPRING 2005
Suppose an economist estimates a consumption function and obtains
the results:
c = 15 + 0.81Yd n = 19, R = .99
(4.8) (0.04)
where c is consumption, n is sample size, Y; is disposable income
and 0.81 is an estimate of