SOLUTION: The Highway Safety Department wants to study the driving habits of individuals.. A sample of 100 cars traveling on the highway revealed an average speed of 60 miles per hour with a

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Question 406446: The Highway Safety Department wants to study the driving habits of individuals.. A sample of 100 cars traveling on the highway revealed an average speed of 60 miles per hour with a standard deviation of 11 miles per hour.
a. Give a point estimate of the population mena
b. Construct an 80% confidence interval estimates for the mean.
c. Construct a 95% confidence interval estimates for the mean
d. Discuss why the 80% and 95% cocnfidence intervals are different
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
The Highway Safety Department wants to study the driving habits of individuals..
A sample of 100 cars traveling on the highway revealed an average speed of 60 miles per hour with a standard deviation of 11 miles per hour.
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a. Give a point estimate of the population mean:: 60 mph
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b. Construct an 80% confidence interval estimates for the mean.
ME = 1.2901 = 1.4192
80% CI: 60-1.2901 < u < 60+1.2901
80% CI: 58.58 < u < 61.2901
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c. Construct a 95% confidence interval estimates for the mean
ME = 1.9842*11/sqrt(100) = 2.1826
95% CI: 60-2.1826 < u < 62.1826
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Cheers,
Stan H.
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d. Discuss why the 80% and 95% cocnfidence intervals are different