STATISTICS WITH ECONOMICS AND BUSINESS APPLICATIONS
PSTAT 5E

Spring 2009
PSTAT 120C:
Solutions to Practice Midterm Questions
April 29, 2009
1. 15.4 (a) There are 7 out of 10 of the twins where student A did better than student B. The
probability of this occurring is
P{M ≥ 7} = 2−10
10
10
10
10
+
+
+
7
8
9
10
= 2−10 (120 + 45 +
STATISTICS WITH ECONOMICS AND BUSINESS APPLICATIONS
PSTAT 5E

Spring 2009
PSTAT 120C:
Assignment # 2
Due April 23, 2009
These problems will be due in lecture next Thursday.
1. Exercise 15.3 from page 748 in WMS.
2. I want to compare the power of a nonparametric test to a typical normal test. Suppose I have
150 independent obser
STATISTICS WITH ECONOMICS AND BUSINESS APPLICATIONS
PSTAT 5E

Spring 2009
Homework 1 Due Monday, April 6th 2009
1. Read through the review material handouts found on my class website,
http:/www.uweb.ucsb.edu/~nbennett/PSTAT120B/120b.htm 2. Read Ch. 1, Sec 6.16.4 3. Hand in the following problems: 1.11 page 12 2.16 page 33 2.76
STATISTICS WITH ECONOMICS AND BUSINESS APPLICATIONS
PSTAT 5E

Fall 2011
Practice Midterm 2
Sections Covered: 5.5, Ch 68 (skip 6.3, 7.7)
Formulas:
If X is a Poisson( ) RV:
P(X=k)=
, E(X)= , Var(X)=
If X is a Uniform(a, b), then f(x) =
and = E[X] =
,
ZTransformation:
CLT: 1. If n
2. If np
30 then
is Normal with mean =
5 and n
STATISTICS WITH ECONOMICS AND BUSINESS APPLICATIONS
PSTAT 5E

Fall 2011
X = $42, 500
= 50, 000
s = $20, 000
= 0.10
H0 :
= 50, 000
HA :
= 50, 000
t
=
=
=
x 0
s/ n
42500 50000
20000/ 20
1.677
0.10 < p value < 0.20
p value >
n
2
z/2 0.25
E2
1.962 0.25
0.0252
1526.64
n = 200
p = 0. 7
p
0.7
0.7
z / 2
1.96
p(1 p)
n
0.7(0.3)
2
STATISTICS WITH ECONOMICS AND BUSINESS APPLICATIONS
PSTAT 5E

Fall 2011
Practice Midterm I Solutions
1.
(1)
(2)
(3)
(4)
(5)
D
A
B
C
B
2.
a) mean = (15+17+99+11+15+16)/6 = 28.83
median: first arrange numbers from least to greatest:
11 15 15 16 17 99
Now, take middle two numbers, average them.
So, median = (15+16)/2 = 15.5
mode
STATISTICS WITH ECONOMICS AND BUSINESS APPLICATIONS
PSTAT 5E

Fall 2011
Practice Problems for MT 1
Related Sections in the textbook: Chapters 15 (skip 2.4, 3.6, 5.5, 5.6)
Youll have 5 problems in the test.
1.
Multiple choice:
(1) Which of the following is an example of quantitative data?
a.
the players number on a baseball u
STATISTICS WITH ECONOMICS AND BUSINESS APPLICATIONS
PSTAT 5E

Fall 2011
Midterm II Study Guide Solutions
1. Hint:
X ~ Binomial Distribution with n=10, and p=0.32
Calculate P(X=5) by binomial prob function (P220) and E(X)=np=3.2
2. Hint:
= 9 claims each week , X=# of claims for one week, X~Poi(9)
P(X=7) =9^7 *e^(9)/7!
P(X=0)=
STATISTICS WITH ECONOMICS AND BUSINESS APPLICATIONS
PSTAT 5E

Fall 2011
PSTAT 5E
Summer 2009 Session A
Name:
Perm:
Midterm 1
Please follow the instructions carefully.
You have 75 minutes (11:00am12:15pm) to complete the exam, and you should attempt all questions.
Be sure to fully explain your answers (except multiple choices
STATISTICS WITH ECONOMICS AND BUSINESS APPLICATIONS
PSTAT 5E

Fall 2011
PSTAT 5E
Summer 2009
Name:
Perm
Midterm 2
Please follow the instructions carefully:
You have 75 minutes to complete the exam, and you should attempt all questions. Be
sure to fully explain your answers. Answers without work will receive no credit.
Anyone
STATISTICS WITH ECONOMICS AND BUSINESS APPLICATIONS
PSTAT 5E

Fall 2012
PSTAT 5A TEST 2 Winter 2010
WWI—
Your TA’s Name: I_
W—
INSTRUCTIONS: FOLLOW CAREFULLY
You have 50 minutes to complete this exam. You should attempt ALL questions. Anyone found copying
another students’ work, or cheating in any other way, will be g
STATISTICS WITH ECONOMICS AND BUSINESS APPLICATIONS
PSTAT 5E

Fall 2012
H: (1&3 L01 ksm /0/y
Worksheet 2
Exercise 1. In April 2003 Science magazine reported a new test for ovarian cancer. Ovarian cancer afﬂicts
1 out of 5000 women. The test is highly sensitive, correctly detecting 99.97% of women who have the disease.
But i
STATISTICS WITH ECONOMICS AND BUSINESS APPLICATIONS
PSTAT 5E

Fall 2011
X
n
(n1) s
n
t /2
p
z /2
p(1p)
n
X 0
t(n1)
s/ n
p p0
p0 (1p0 )
n
Z
(X1 X2 ) D0
s2
1
n1
+
s2
2
n2
t(mincfw_n1 1,
n2 1)
d d
t(n1)
sd / n
(1 p2 )
p
p(1 p)( n1 +
1
1
)
n2
Z,
p=
n1 p1 + n2 p2
X1 + X2
=
n1 + n2
n1 + n2
/ n
STATISTICS WITH ECONOMICS AND BUSINESS APPLICATIONS
PSTAT 5E

Fall 2011
Sample Final Exam
PSTAT 5E, Fall 2011
1. A group of 24 randomly selected students have a mean score of 30.8 with a standard deviation of 4.5
on a placement test. Assume that these data come from a population that is normally distributed.
What is the 90% c
STATISTICS WITH ECONOMICS AND BUSINESS APPLICATIONS
PSTAT 5E

Fall 2011
Formulas for Final Exam
Creating a condence interval for , the margin of error is t/2
(n1) s
n
.
Testing for a population mean:
X 0
t(n1)
s/ n
Testing for the dierence between two means in independent samples:
(X1 X2 ) D0
s2
1
n1
+
s2
2
n2
t(mincfw_n
STATISTICS WITH ECONOMICS AND BUSINESS APPLICATIONS
PSTAT 5E

Fall 2011
Y
=
you understand
F
=
f riend understands
P (Y )
=
0.5
P (F )
=
0.6
P (Y F )
=
0.25
P (Y )P (F ) = 0.5 0.6 = 0.3 = 0.25
P (Y )P (F ) = P (Y F )
P (Y C F )
P (F )
=
0.6
=
0.35
=
P (Y F ) + P (Y C F )
0.25 + P (Y C F )
P (Y C F )
S
T
=
=
taking steroids
te
STATISTICS WITH ECONOMICS AND BUSINESS APPLICATIONS
PSTAT 5E

Spring 2009
PSTAT 5E, Winter 2006
Wang
January 27, 2006
PSTAT5E Homework 4
Practice HW
4.1, 4.2, 4.5, 4.18, 4.20(a)(b)(c), 4.21, 4.24, 4.31, 5.1, 5.4, 5.10, 5.24, 5.25, 5.26, 5.64, 5.67,
5.71
Extra Find z0 for the following probabilities.
(a) P (z > z0 ) = .05.
(b) P
STATISTICS WITH ECONOMICS AND BUSINESS APPLICATIONS
PSTAT 5E

Spring 2009
PSTAT 5E, Fall 2004
Wang
March 3, 2006
PSTAT5E Homework 7
Note: use the pvalue approach to hypothesis testing
Practice HW
8.1(a)(b)(c), 8.2, 8.3,
Extra: test hypotheses in above three questions using α = .05.
8.9, 8.13(a)(c)(e), 8.14, 8.26(a)(b)(e), 8.28
STATISTICS WITH ECONOMICS AND BUSINESS APPLICATIONS
PSTAT 5E

Spring 2009
2.46.
a. The first variable (X) is the first number in the pair and is plotted on the horizontal axis, while the
second variable (Y) is the second number in the pair and is plotted on the vertical axis. The scatterplot
is shown in the figure below:
b. The
STATISTICS WITH ECONOMICS AND BUSINESS APPLICATIONS
PSTAT 5E

Spring 2009
PSTAT5E
Practice Homework 1
Solutions
1.1.
a. The population of interest is the population of measurements consisting of the number
of a particular item that will be demanded by customers in a particular month, measured for
all months, in the past and on
STATISTICS WITH ECONOMICS AND BUSINESS APPLICATIONS
PSTAT 5E

Spring 2009
PSTAT 5E
Quiz Homework 1
Solutions
1.7.
a. The population consists of shopper opinions (‘prefer’ or ‘do not prefer’ background
music) for all shoppers who might patronize the supermarket, now or in the future.
b. It would not be possible to enumerate the