(7 pages; revised 04/04/08)
Page
1
of 2201 Quiz 03
Louisiana State University
EXST 2201
Quiz 03
Spring 2008
Name: _________________________
Section: __________ Score: __________
Due:
Week of April 14, 2008
(100 pts)
Directions
:
Put your answer (letter) in the associated blank. You may use any book and talk to any person.
You do not have to show your work to get credit.
1.
Classify the following scenarios.
A.
Sample 1: The weights (lbs) of
19 newborn females.
_____ (3 pts)
Sample 2: The weights (lbs) of
19 newborn males.
a) Pairedsamples.
b) Independent samples.
B.
Sample 1: The scores (points) of 13 students who took the ACT.
_____ (3 pts)
Sample 2: The scores (points) of 13 other students who took the SAT.
a) Pairedsamples.
b) Independent samples.
C.
Sample 1: The pretraining weights (lbs) of 17 athletes.
_____ (3 pts)
Sample 2: The posttraining weights (lbs) of the same 17 athletes.
a) Pairedsamples.
b) Independent samples.
2. A weightlifting coach claims that weightlifters can increase their strength by taking a
certain supplement. To test his theory, the coach randomly selects 9 athletes and gives
them a strength test using a bench press. Thirty days later, after regular training using the
supplement, they are tested again. The results are listed below. Test the claim that the
supplement is effective in increasing the athlete’s strength. Use significance 0.10 and
assume that the data are distributed normally.
Before:
215
240
188
212
275
260
225
200
182
After:
225
245
188
210
282
275
230
195
190
Difference:
10
5
0
2
7
15
5
5
8
n
d
bar
s
Difference:
9
4.78
6.24
A. What is the appropriate set of hypotheses (H0, H1)?
_____ (3 pts)
a)
mu
(d) = 0,
mu
(d)
.ne. 0
b)
mu
(d)
.ne. 0,
mu
(d)
= 0
c)
mu
(d) = 0,
mu
(d)
<
0
d)
mu
(d)
=
0,
mu
(d)
> 0
B. What is the correct value of the test statistic?
_____ (3 pts)
a) 2.30
b)
6.51
c) 4.44
d) 6.51
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C. What is the correct
P
value for this test statistic?
_____ (3 pts)
a) 0.025
b) 0.050
c) 0.020
d) 0.100
D.
Does the supplement significantly increase the athlete’s strength?
_____ (4 pts)
a) Yes.
b) No.
c) Sometimes.
d) Depends on distribution.
3. A study was conducted to determine if the salaries of elementary school teachers from
two neighboring districts were equal. A sample of 15 teachers from each district was
randomly selected. Test the claim that the salaries from both districts are equal. Use
significance 0.05 and assume that the data are distributed normally.
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 Summer '08
 McKenna
 Normal Distribution, pts, Statistical hypothesis testing, Student's ttest

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