SOLUTION: In a random sample of 24 ​people, the mean commute time to work was 30.8 minutes and the standard deviation was 7.1 minutes. Assume the population is normally distributed and

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Question 1129450: In a random sample of 24 ​people, the mean commute time to work was 30.8 minutes and the standard deviation was 7.1 minutes. Assume the population is normally distributed and use a​ t-distribution to construct a 95​% confidence interval for the population mean mu. What is the margin of error of mu​? Interpret the results.
The confidence interval for the population mean mu is left parenthesis comma right parenthesis .
​(Round to one decimal place as​ needed.)
The margin of error of mean is:

​(Round to one decimal place as​ needed.)
Interpret the results.
A.
It can be said that 95​% of people have a commute time between the bounds of the confidence interval.
B.
With 95​% ​confidence, it can be said that the commute time is between the bounds of the confidence interval.
C.
With 95​% ​confidence, it can be said that the population mean commute time is between the bounds of the confidence interval.
D.
If a large sample of people are taken approximately 95​% of them will have commute times between the bounds of the confidence interval.

Answer by Boreal(15235)   (Show Source): You can put this solution on YOUR website!
t df=23,0.975=2.069
s=7.1
ts/sqrt(n) is half interval or 2.069*7.1/sqrt(24)=3.0 ANSWER
(27.8, 33.8)units minutes
C
The purpose of a confidence interval is to define where the true mean lies, with a certain degree of confidence. The true mean is usually unknown and unknowable and either lies in or out of the interval. We don't know which, and it is a 100-0 type of issue, which is why we use confidence for where we think the true mean lies, not a probability.

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