Final Exam  Spring 2002  ST 370 Online  A
Darken the circle on the answer sheet corresponding to your answer. Use a number 2 pencil. Stray
marks on the form may cause errors. All questions are worth 3 points.
1. An important distinction in the second half of the course is between discrete and continuous
random variables. Which one of the following types is a discrete random variable?
A. normal
B. binomial
C. Weibull
D. exponential
E. None of the above
2. The 67th percentile is
A. the point such that 33 percent of the data lies below it
B. close to the standard deviation
C. the point such that 67 percent of the data lies below it
D. close to the interquartile range
E. None of the above
3. Which of the following are measures of variability (or dispersion)?
A. standard deviation
B. sample range
C. interquartile range
D. All of the above
E. None of the above
4. The probability that a standard normal random variable
Z
lies above

1
.
44 is given by
A. .0912
B. .9839
C. .9251
D. .0833
E. None of the above
5. Suppose that a small sample is given by 3.56, 2.78, 1.24, 4.44. The sample standard deviation is
A. 1.358
B. 1.844
C. 3.005
D. 1.540
E. None of the above
1
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View Full Document6. In the early lesson on hypothesis testing, the following statement was found in the summary
(talking about comparing two population mean values):
The p value is a useful measure of evidence against the null hypothesis. But one must be careful
because a small p value can be due to either
(i) a large population mean diﬀerence and small sample sizes
or
(ii) a small population mean diﬀerence and large sample sizes.
For which of those two situations would we say we have a
statistically signiﬁcant
result but not
likely a
practically signiﬁcant result
?
A. (i)
B. (ii)
7. When is
Pr
(
A
or
B
)=
Pr
(
A
)+
Pr
(
B
)?
A. Always.
B. Never.
C. Only when
A
and
B
are statistically independent events.
D. Only when
A
and
B
are mutually exclusive events.
E. None of the above.
8. When is
Pr
(
A
and
B
)=
Pr
(
A
)
Pr
(
B
)?
A. Always.
B. Never.
C. Only when
A
and
B
are statistically independent events.
D. Only when
A
and
B
are mutually exclusive events.
E. None of the above.
9. We are studying a population with unknown mean
μ
and standard deviation that we guess is
around 3. We plan to take a random sample and want to construct a 95% conﬁdence interval of
length 2 (right endpoint

left endpoint = 2). How large should the sample size be?
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 Spring '08
 Nail
 Normal Distribution, Standard Deviation, d., c.

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