Question 1168474: In a random sample of 28 people, the mean commute time to work was 31.2 minutes and the standard deviation was 7.3 minutes. Assume the population is normally distributed and use a​ t-distribution to construct a 98% confidence interval for the population mean μ. What is the margin of error of μ? Interpret the results.
-The confidence interval for the population mean μ is ( , )?
-The margin of error of μ is ( )?
-Interpret the resluts.
A. with 98% confidence, it can be said that the population mean commute time is between the bounds of the confidence interval.
B. With 98% confidence, it can be said that the commute time is between the bounds of the confidence interval.
C. If a large sample of people are taken approximately 98% of them will have commute times between the bounds of the confidence interval.
D. It can be said that 98% of people have a commute time between the bounds of the confidence interval.
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! half-interval is t(0.99, df=27)*s/sqrt(n)
=2.47*7.3/sqrt(28)
=3.41. This is the margin of error.
so the 98% CI is mean +/- 3.41
this is (27.8, 34.6) min the 98% CI
We don't know the exact mean for the commute interval, but we are 98% confident it lies in this interval.
If we took multiple samples of 28, 98% of them would contain the true mean, but we wouldn't know which 98.
This is A. CIs discuss parameters.
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