2/6/12
What You (Really) Need to Know - NYTimes.com
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ST422
Spring, 2013
Quiz 1
Name: (10 points)
Directions: Answer questions as directed. Please show work. Give expressions for answers
where possible. Unsolved integrals that are correctly written with correct limits will receive
partial credit. The space p
ST422
Spring, 2013
Quiz 1
Name: (10 points)
Directions: Answer questions as directed. Please show work. Give expressions for answers
where possible. Arithmetic such as division and multiplication is not necessary when correct
solutions are given that invo
ST422
Spring, 2013
Quiz 2 - SOLUTIONS
1. Suppose Y1 , . . . , Yn is a random sample from the exponential distribution with unknown
mean , with pdf given by
1
f (y ; ) = ey/ (y > 0).
(a) Which of the following is the cumulative distribution function of Y ?
Solutions to Prof. Gerigs ST 422 Midterm Examination II, dated March 24, 2008
1. (a) (Maximum likelihood sont be covered on Exam 2, ST422, Spring 2012)
= f (y1 , . . . , yn |)
L()
n
=
i=1
log L()
=
n
2
n
1
log(2)
x2
i
2
2
n
1
set
x2 = 0
+2
i
2
2
1
x2
i
2
ST422
Tom Gerig 1
ST422
Midterm Examination II
March 24, 2008
Closed book and notes. You may use one sheet of notes (8 by 11, both
sides). You will need a calculator.
NAME: _
Row #: _
Before you turn in your examination, please sign and date the following
ST 422
Midterm Exam 1
(Professor Judy Wang)
02/09/2011
1. An experiment to determine the eects of temperature on the survival of insect eggs was
described in the paper Development Rates and a Temperature Dependent Model of Pales
Weewil (Environ. Entomolog
ST 422
Midterm Exam 1
(Professor Judy Wang)
(Solutions)
02/09/2011
1. An experiment to determine the eects of temperature on the survival of insect eggs was
described in the paper Development Rates and a Temperature Dependent Model of Pales
Weevil (Enviro
ST 422
Final Exam
05/06/2011
Instructor: Huixia Judy Wang
Your Name (Print):
Your ID:
Notes:
1. There are total 4 problems.
2. Be sure to show all your work; your partial credit might depend on it.
3. NO CREDIT will be given without supporting work.
4. Th
ST422 Final - Dr. Wang - Solutions
1. Let X1 , X2 , X3 , Y1 , Y2 , Y3 , Y4 be independent random variables from N ( = 3, 2 = 4) and
1
X=
3
3
i=1
1
Xi , Y =
4
4
Yi ,
i=1
2
SX
1
=
2
3
1
2
(Xi X )2 , SY =
3
i=1
4
(Yi Y )2 .
i=1
Find the distribution of the f
ST 422
Makeup Exam
04/19/2011
Instructor: Huixia Judy Wang
Your Name (Print):
Your ID:
Notes:
1. There are total 4 problems.
2. Be sure to show all your work; your partial credit might depend on it.
3. NO CREDIT will be given without supporting work.
4. T
ST422 Final - Wang - Solutions
1. (40 points) Let Y1 , , Yn be a random sample from the distribution with pdf :
11
f (y ) = y 1 , 0 y 1.
(a) (13 points) Find the method of moment estimator of . Is it consistent to and why?
Recognizing that Y has the beta
ST421
Quiz 1 - practice problems - solutions
1. (a)
FU (u) = P (U u)
= P (2Y 1 u)
u+1
= P (Y
)
2
(u+1)/2
4y 3 dy
=
=
0
0
u+1 4
2
1
u < 1
(1 < u < 1)
u>1
(b) FU (0) = (1/2)4 = 1/16
(c) f (u) = F (u) = 4/16(u + 1)3
(1 < u < 1)
(d) E (U ) = E (2Y 1) = 2E (Y
2/6/12
What Are the Odds That Stats Would Be This Popular? - NYTimes.com
JANUARY 26, 2012, 10:30 AM
What Are the Odds That Stats Would Be This Popular?
By Q UENTIN HARDY
Most of my life I went to parties and heard a little groan when people heard what I d
ST422
Quiz 1 - practice problems
1. Suppose that Y is a beta random variable with pdf
f (y ) = 4y 3
(0 < y < 1)
Let U = 2Y 1.
(a) Derive the cdf of U .
(b) Find P (U < 0).
(c) Derive the pdf of U .
(d) Find the mean of U .
2. Suppose that X and Y are inde
ST422
Spring, 2012
Quiz 1
Name: (10 points)
Directions: Answer questions as directed. Please show work. Give expressions for answers
where possible. Arithmetic such as division and multiplication is not necessary when correct
solutions are given that invo
ST422
Spring, 2012
Quiz 2
Name:
Directions: Answer questions as directed. Please show work. You are advised not to leave
any answers blank.
There are four questions, each worth 25 points.
Any academic misconduct observed by exam proctors will be documente
ST422
Spring, 2012
Quiz 2
Solutions
iid
1. Let X1 , . . . , Xn N (, 2 ).
(a) Suppose n = 100 and these statistics are observed: x = 20, s = 2. Report a 95%
condence interval for .
s
x 1.96 or 20 1.96(0.2) or 20 .39
n
(b) Refer to the interval from part (a
ST422
Tom Gerig 1
ST422
Final Examination
April 30, 2008
Closed books and notes. You may use two pages of notes (8 by 11, both
sides, any content). You will need a calculator. Tables are attached to the back
of the examination.
NAME: _
Row #: _
Before you
Solutions to Dr. Gerigss Final from Spring, 2008
1. (a) H0 : T C = 0 vs Ha : T C > 0
(b) Test Statistic: T = (XT XC )/
R.R. cfw_T > t22,.05 = 1.72
Observe
tobs =
2
Sp (1/nT + 1/nC )
9.95
49.07 39.12
=
= 1.88
157.1(1/15 + 1/9)
5.29
which is in the R.R. The
ST 422 Homework Assignment 9
Due date:
Student name:
Reading: Chapter 10 - through 10.9
1. (10.54) Do you believe that handedness is associated with success in business? Suppose it is known
that 85% of the general public is right-handed. A survey of n = 3
ST 422 Homework Assignment 8
Due date:
Student name:
Reading: Chapter 10
1. (10.2) A drug is claimed to bring about sleep in 80% of a population suering from insomnia. A
researcher investigates the claim by giving the drug to a random sample of n = 20 ins
ST422, Spring, 2013
Diagnostic Quiz (counts as one homework assignment)
Full credit assigned with evidence of eort on each problem. If you do not know how to solve
the problem, please indicate this with DK for (Dont know, or Cant remember.).
1. Suppose a
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ST422
Spring, 2012
Final Exam
Name:
Directions: Answer questions as directed. Please show work. You are advised not to leave
any answers blank.
There are six questions, each worth 20 points, for a total of 120 points.
Any academic misconduct observed by e
ST422
Tom Gerig 1
ST422
Midterm Examination I
February 13, 2008
Closed book and notes. You may use one sheet of notes (8 by 11, both
sides). You will need a calculator.
NAME: _
Row #: _
Before you turn in your examination, please sign and date the followi