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Practice Test 11
AP Statistics
Name:
Directions:
Work on these sheets.
Tables and formulas appear on a separate sheet.
Part 1:
Multiple Choice.
Circle the letter corresponding to the best answer.
1.
The heights (in inches) of males in the United States are believed to be normally distributed with
mean
µ
. The average height of a random sample of 25 American adult males is found to be
x
= 69.72
inches and the standard deviation of the 25 heights is found to be
s
= 4.15. The standard error of
x
is
(a) 0.17
(b) 0.69
(c) 0.83
(d) 1.856
(e) 2.04
The next two questions refer to the following situation:
In some mining operations, a byproduct
of the processing is mildly radioactive. Of prime concern is the possibility that release of these
byproducts into the environment may contaminate the freshwater supply. There are strict
regulations for the maximum allowable radioactivity in supplies of drinking water, namely an
average of 5 picocuries per liter (pCi/L) or less. However, it is well known that even safe water has
occasional hot spots that eventually get diluted, so samples of water are assumed safe unless there
is evidence to the contrary. A random sample of 25 specimens of water from a city’s water supply
gave a mean of 5.39 pCi/L and a standard deviation of 0.87 pCi/L.
2.
The appropriate null and alternative hypotheses are:
(a)
H
0
: µ = 5.39 vs H
a
: µ
≠
5.39
(b)
H
0
: µ = 5.39 vs H
a
: µ < 5.00
(c)
H
0
: µ = 5 vs H
a
: µ = 5.39
(d)
H
0
: µ = 5 vs H
a
: µ < 5
(e)
H
0
: µ = 5 vs H
a
: µ > 5
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 Spring '11
 Smith
 Statistics

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