Question

Suppose data collected by observers at randomly selected intersections across the country revealed that in a sample of 40 drivers, 20 were using their cell phone.

a. Give a point estimate of p, the true driver cell phone use rate (that is, the true proportion of drivers who are using their cell phone while driving).

b. Compute a 90% confidence interval for p. c. Give a practical interpretation of the interval, part b.

Answer #1

Suppose that a safety group surveyed 1,300 drivers. Among those
surveyed, 76% said that careless or aggressive driving was the
biggest threat on the road, and 37% said that cell phone usage by
other drivers was the driving behavior that annoyed them the most.
Based on these data and assuming that the sample was a simple
random sample, construct and interpret a 90% confidence interval
estimate for the true proportion in the population of all drivers
who are annoyed by...

In a July 2001 research note, the U.S. Department of
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level of cell phone use by drivers while they are driving a motor
passenger vehicle. Data collected by observers at randomly selected
intersection across the country revealed that in a sample of 1165
drivers, 35 were using their cell phone.
(a) Check and verify the two conditions for a 98%...

Environmental engineers are using data collected by weather data
centers to learn how climate affects the sea ice. Of 511 ice melt
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"first-year ice". The researchers estimated that about 16% of melt
ponds in the region have first-year ice. Estimate, with 90%
confidence, the percentage of all ice-melt ponds in the region
that have first-year ice. Give a practical interpretation of the
results.
Construct a 90% confidence interval around the...

Environmental engineers are using data collected by weather data
centers to learn how climate affects the sea ice. Of 515 ice melt
ponds studied in a certain region, 78 were classified as having
"first-year ice". The researchers estimated that about 15% of melt
ponds in the region have first-year ice. Estimate, with 90%
confidence, the percentage of all ice-melt ponds in the region
that have first-year ice. Give a practical interpretation of the
results.
Construct a 90% confidence interval around...

A study by Allstate Insurance Co. finds that 82% of teenagers
have used cell phones while driving (The Wall Street Journal, May
5, 2010). In October 2010, Massachusetts enacted a law that forbids
cell phone use by drivers under the age of 18. A policy analyst
would like to determine whether the law has decreased the
proportion of drivers under the age of 18 who use a cell phone.
which one is correct H0 and H1 statement?
a.
H0: proportion...

The authors of a paper describe an experiment to evaluate the
effect of using a cell phone on reaction time. Subjects were asked
to perform a simulated driving task while talking on a cell phone.
While performing this task, occasional red and green lights flashed
on the computer screen. If a green light flashed, subjects were to
continue driving, but if a red light flashed, subjects were to
brake as quickly as possible. The reaction time (in msec) was
recorded....

Suppose that a market research firm is hired to estimate the
percent of adults living in a large city who have cell phones. 500
randomly selected adult residents in this city are surveyed, 481
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interval for the true proportion of adults residents in this city
who have a cell phone. Then give a complete
confidence statement. Round only the last calculation
(both endpoints of the interval) to two decimal places.

A survey of 100 randomly selected Michigan residents finds that
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independent study of a 100 randomly selected California residents
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movies. Assume that the population standard deviation for the
Michigan residents is $5 per month and that the population standard
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Use the sample data and confidence level given below to complete
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In a study of cell phone use and brain hemispheric dominance,
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(Round to three decimal places as needed.)
b) Identify the value...

In a survey of randomly selected adults, 480 of them believe the
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a. What parameter are we estimating?
b. Explain the requirements as they relate to the problem.
c. What is the point estimate of the parameter?
d. Input the margin of error for a 90%
confidence interval for the true proportion of...

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