STAT 205
Exam 2
Name ______ANSWER KEY
________
Fall 2006
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View Full DocumentPart I: Answer eight of the following nine questions. If you complete more than eight, I
will grade only the first eight. Five points each.
1) State the definition of a Pvalue.
The probability under H
0
of observing a test statistic as extreme or more extreme (in the
direction of H
A
) as that actually observed.
2) (Circle the correct answer) A hypothesis test has been conducted at the 0.05
significance level, resulting in a Pvalue of 0.003. Obviously, in this case, we reject H
0
.
If an error was made, it would be a
Type I / Type II / neither
error.
3) (Circle the correct answer) Suppose you have calculated a 95% confidence interval for
the mean,
μ
. Now, you want to calculate a 99% confidence interval using the same sample.
The 99% confidence interval will be
narrower / wider
than the 95% confidence interval.
4) Consider taking a random sample of size 4 from a population of persons who smoke
and recording how many of them, if any, have lung cancer. Let
p
ො
represent the proportion
of persons in the sample with lung cancer. List the possible values of
p
ො
.
0, 0.25, 0.5, 0.75, 1
5) (Circle the correct answer) Trichotillomania is a psychiatric illness that causes its
victims to have an irresistible compulsion to pull their own hair. Two drugs were
compared as treatments for trichotillomania in a study involving 13 women. Each woman
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 Fall '09
 Hendrix
 Statistics, Normal Distribution, Statistical hypothesis testing

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