Elementary Statistics Chapter 6 Test  Form C
Name:___________________________ Course Number: __________ Section Number: _____
SHORT ANSWER. Write the word or phrase that best completes each statement or answers the question.
Provide an appropriate response.
1) How do you determine whether to use the z or t distribution in computing the margin of error,
E = z
a/2 œ s
n
or E = t
a/2 œ s
n
?
2) The BideaWhile efficiency hotel, which caters to business workers who stay for extended
periods of time (weeks or months), offers room service. In a small study of 35 randomly selected
room service orders, the 95% confidence interval for mean delivery time for room service is
24.8 < m < 29.6 minutes. The marketing director is trying to determine if she can advertise "room
service in under 30 minutes, or the order is free." How would you advise her?
3) Explain how confidence intervals might be used to make decisions. Give an example to clarify
your explanation.
4) Why is s2 the best point estimate of s2 ?
MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the
question.
Solve the problem.
5) Find the value of za/2 that corresponds to a level of confidence of 96.68 percent.
A) 2.13 B) 1.84 C) 0.0166 D) 2.13
6) The following confidence interval is obtained for a population proportion, p:
(0.283, 0.323)
Use these confidence interval limits to find the point estimate, p^ .
A) 0.323 B) 0.308 C) 0.283 D) 0.303
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Find the margin of error for the 95% confidence interval used to estimate the population proportion.
7) In a survey of 5400 T.V. viewers, 30% said they watch network news programs.
A) 0.00915 B) 0.0140 C) 0.0122 D) 0.0160
Use the given degree of confidence and sample data to construct a confidence interval for the
population
proportion p.
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 Spring '16
 Christy Turner
 Statistics, Normal Distribution

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