University of Colorado Department of Economics Economics 3818 Prof. Jeffrey S. Zax Midterm Examination 27 September 2005
Solutions Consider two outcomes C and D, where Pr(C)=.3, Pr(D)=.5, Pr(C1D)=.3 (3) a. What is Pr(CcD)? Why? Pr(CcD) = Pr(C) + Pr(D) ! P
Answer Key to Problem Set 6
Fall 2005 Econ 3818-300
Answer Key to Problem Set 6
a. Schedule: Assigned Tuesday, 11 October. Due Tuesday, 18 October in class. b. Problems: 3.14, 3.18, 7.8, 8.2, 8.4 and 8.6 in "Statistics for Economics: An Intuitive Approach
Answer Key to Problem Set 5
Fall 2005 Econ 3818-300
Answer Key to Problem Set 5
a. Schedule: Assigned Tuesday, 4 October. Due Tuesday, 11 October in class. b. Problems: 6.18, 6.20, 6.30, 7.2, 7.4, and 7.6 in "Statistics for Economics: An Intuitive Approac
Problem Set #3
Note: this problem set is Due by Wednesday, 12 noon, February 3. Solutions will be
available at that time. It may be handed in in class Tuesday, in recitation, or in the folder
on my office door.
Bayes Law; Discrete and Continuous Random Va
Problem Set 1 Answer Guide
1) Total tax = 500 = 500(200 + 0.1 ) = 200 500 + 0.1 500 . As the total
1
=1
=1
income of the geographical area is $5,000,000 we know that 500 = $5,000,000. Thus, we
=1
have, 200 500 + 0.1 $5,000,000 = $, .
2)
Mean
Variance
Stan
Econ 3818
Problem Set # 6
Suggested Solutions
1. a. The 8 "& Estimate will have smaller variance.
b. Both unbiased (mean .).
Z .
s"
" 5#
" 5#
% "! % "&
% 5#
* 5#
Z .
s#
#& "! #& "&
So I would choose .
s"
2 a. In this context it means if Ms. Jones overes
Quiz #5
Suggested Solutions
1.
Suppose the annual return to a stock \ is normally distributed with mean .12
and variance .04. You invest in this stock. What is the probability you will make more
than 20%?
Given \ R "# !%. Find T \ !#
T \ !# T
\ "#
!#! "#
Quiz #2
Suggested Solutions
1. (two points) My foul shooting has really gone into the tank, so that currently I only
score with probability .4 What is the probability it takes me three shots to score?
Using the hypergeometric probability mass function wit
Suggested Solutions
Quiz #$
1.
I need an estimate of the number of employees needed to staff the return counter
at Walmart. Customers come in randomly over store hours to return products. Which
distribution would I turn to?
Discrete Uniform
Geometric
Bern
Econ 3818
Problem Set # 5
I \ ( Z \ #& "#&
1.
I \ ] I \ I ] "#
Z \ ] Z \ Z ] #G \ ] !)
2a
b.
Suggested Solutions
I #] #I ] "%
Z #] %Z ] $#
So the portfolio #] has a higher return than the
portfolio \ ] , but a much higher variance, so depending upon my ta
Quiz #4
Suggested Solutions
1. (1) The formula for the covariance of two random variables is_0 _ .
+ G \ ] I \ .B ] .C
, G \ ] B3 C4 T \ B3 ] C4
3
4
- G \ ] I \] I \ I ]
. + and ,
/ + and -
0 + , and 2. (1 point each) True of false (no explanation nece
Econ 3818
Problem Set # (
Suggested Solutions
1.
(two points each)
Consider a population with unknown mean . but known
#
variance 5 25. In a random sample of size 36 we find \ )
a. Find the 95% confidence interval for the population mean .
. '$% *'
b. Fin
University of Colorado Department of Economics Economics 3818 Prof. Jeffrey S. Zax Midterm Examination 3 November 2005
Solutions
(32)
1.
X and Y have the following joint distribution: Y x1=2 x2=4 x3=6 y1=2 .2 .1 .2 y2=4 .1 .1 .3
X
(1)
a.
What is P(X=4, Y=
Answer Key to Problem Set 9
Fall 2005 Econ 3818-300
Answer Key to Problem Set 9
Schedule: Assigned Tuesday, 8 November. Due Tuesday, 15 November in class. Problems: 9.2, 9.8, 9.10, 9.12, 9.16 and 9.18 in "Statistics for Economics: An Intuitive Approach",
Answer Key to Problem Set 8
Fall 2005 Econ 3818-300
Answer Key to Problem Set 8
Assigned Tuesday, 25 October. Due Tuesday, 1 November in class. Problems: 8.20, 8.22, 8.24, 8.26, 8.28 and 8.30 in "Statistics for Economics: An Intuitive Approach", by Allan
Answer Key to Problem Set 7
Fall 2005 Econ 3818-300
Answer Key to Problem Set 7
Schedule: Assigned Tuesday, 18 October. Due Tuesday, 25 October in class. Problems: 8.8, 8.10, 8.12, 8.14, 8.16 and 8.18 in "Statistics for Economics: An Intuitive Approach",
Problem Set 2 Solutions
1) Start with 100 kids at the school. 48 are boys, 52 are girls. Let M be the event that the child is a
boy and F the event that the child is a female. Also, let T be the event that a child is on the track
team and S be the event t