STA 6126
Exam 2
1.
Based on responses of 1600 subjects in General Social Surveys in the mid1980s, a
95% Confidence Interval for the mean number of close friends equals (5.6, 7.2). For
each statement, circle the best response:
Correct
or
Incorrect
.
a)
If random samples of 1600 were repeatedly selected and 95% Confidence
intervals computed based on each sample, then in the long run 95% of the
intervals would contain the true mean.
Correct
b)
We can be 95% confident that
Y
is between 5.6 and 7.2.
Incorrect
c)
95% of respondents had between 5.6 and 7.2 close friends.
Incorrect
d)
We can be 95% confident that \mu is between 5.6 and 7.2.
Correct
2.
The
P
value for testing H
0
: \mu=100
vs
H
A
: \mu
≠
100 is 0.001 and
100
<
Y
. This
indicates strong evidence that (select the correct answer):
a)
\mu<100
b) \mu>100 c) \mu=100
3.
A largesample 95% confidence interval for \mu_1\mu_2 is (2.0, 7.0). The
P
value
for testing H
0
: \mu_1\mu_2=0
vs
H
A
: \mu_1\mu_2
≠
0 based on the same sample
data is (select the correct answer):
a)
above 0.05
b)
below –0.05
c)
below 0.05
d)
Need more information
4.
Researchers reporting a Ztest to test the alterntative hypothesis that the proportion of
males favoring a candidate is larger than the proportion of females favoring the
candidate (H
A
:\mu_
M
\mu_
F
> 0) give a
P
value of
0.0643. Their computed test
statistic was:
a)
0.0643
b)
1.52
c)
1.85
d)
0.9357
e)
We need more information
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View Full DocumentFor each of the following problems, give the null and alternative hypotheses (be very
careful in notation with respect to symbols and subscripts)
5.
Researchers believe that when faced with the question: “Do you have a favorable
attitude toward President Bush”?, men are more likely to respond “Yes” than women.
Ho: p_malep_female≤0
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 Spring '08
 YESILCAY
 Statistics, Normal Distribution, Standard Deviation, vs ha, adverse event rate

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