SOLUTION: Question 5
A sociologist found that in a random sample of 50 retired men, the average number of jobs they had during their lifetimes was 7.2. The population standard deviation is
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A sociologist found that in a random sample of 50 retired men, the average number of jobs they had during their lifetimes was 7.2. The population standard deviation is
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Question 1183831: Question 5
A sociologist found that in a random sample of 50 retired men, the average number of jobs they had during their lifetimes was 7.2. The population standard deviation is 2.1.
a. Find the best point estimate of the population mean.
b. At 80% confidence level, estimate the margin of error.
c. Find the 80% confidence interval of the mean number of jobs.
d. How large a sample would be required if you want to be 99% confidence within 0.05?
e. Estimate the sample mean if at 95% confidence level, the confidence intervals is 52.3 < 𝜇 < 55.7.
f. Find the error bound at 80% confidence level using the 80% confidence interval calculated. Answer by Boreal(15235) (Show Source):
You can put this solution on YOUR website! Point estimate is 7.2 the sample value
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80% CI half interval is z(0.90)*sigma/sqrt(n)
=1.282*2.1/sqrt(50)
=0.38. This is the margin of error (B)
the interval is (6.82, 7.58) units jobs (C)
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error=z(0.995)*sigma/sqrt(n)
0.05=2.576*2.1/sqrt(n)
sqrt(n)=2.576*2.1/0.05=108.192
square both sides and n=11705.50 or 11706 people
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The mean will be in the middle or 54.0
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The error bound for the 80% interval is 7.58-7.2 or 0.38 jobs
