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Name:__________________
Section:
Statistics 311
Final Exam
11 December 2007
E:\Stat311\Autumn2007\FinalExamAu07Solutions.doc
1
__________
Please read the following instructions carefully.
Do not turn the page and start the exam until you
are told to begin.
You may have the formula card that comes with the textbook (or a copy of the same).
You may also
have one sheet (doublesided) of 8.5 x 11 paper with notes (handwritten or typed).
You may use a
calculator, although be sure to show your work.
There are 3 multipart short answer problems worth a total of 98 points; you get 1 point for your name
and 1 point for your quiz section.
In addition, there are 5 multiple choice problems and 5 true/false
problems.
The multiple choice and true/false problems are worth one point each for up to 10 points of
extra credit.
Point values for each question or part of a question are designated in parentheses at the
beginning of the problem.
GOOD LUCK!
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The data set is from exercise 10.64 in Neil Weiss’
Introductory Statistics
, 8
th
edition, 2008, Pearson Education, Inc. Data are from a
paper by Lee and Dunton, M
arine Ecology Progress Series
, 2000, Vol. 196, pp. 3948.
2
Problem 1 (6+10+4+6):
Researchers of the Marine Science Institute of the University of Texas at
Austin noticed a difference in the seagrass beds in Corpus Christi Bay (CCB) versus those in Lower
Laguna Madre (LLM).
Researchers know that ammonium is essential to seagrass growth.
As such,
they decided to compare sediment (pore water) ammonium concentrations (in
M
µ
) at the two
locations.
Summary statistics based on collected samples are given below
*
.
CCB
CCB
CCB
LLM
LLM
LLM
115 1
79 4
51
24 3
10 5
19
x.
s
.
n
s.
n
==
=
=
a)
Write down the null and alternative hypotheses to test whether, on average, ammonium
concentrations at CCB are greater than those at LLM.
Be sure to appropriate label your
parameters.
01
:
or
= 0
versus
:
or
0
CCB
LLM
CCB
LLM
CCB
LLM
CCB
LLM
HH
µµ
=−
>−
>
b)
Construct the appropriate test statistic for your test in part a) using an unpooled procedure.
()
2
2
0
115 1
24 3
0
90 8
90 8
90 8
798
11 376
6304 36
110 25
123 615
5 803
129 418
51
19
CCB
LLM
obs
CCB
LLM
CCB
LLM
xx
. .
..
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This test prep was uploaded on 04/07/2008 for the course PHI 311 taught by Professor Tamre during the Spring '08 term at University of Washington.
 Spring '08
 Tamre

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