Hank and Debra each one two milking cows. One day, they Milked their cows and compared the amount of milk the cows produced in t
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Answer:
The 99% confidence interval for the mean commute time of all commuters in Washington D.C. area is between 22.7994 minutes and 33.1406 minutes. The interpretation is that we are 99% sure that the true mean ommute time of all commuters in Washington D.C. area is between 22.7994 minutes and 33.1406 minutes.
Step-by-step explanation:
We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of .
So it is z with a pvalue of , so
Now, find M as such
In which is the standard deviation of the population and n is the size of the sample.
The lower end of the interval is the mean subtracted by M. So it is 27.97 - 5.1706 = 22.7994 minutes
The upper end of the interval is the mean added to M. So it is 6.4 + 0.3944 = 33.1406 minutes.
The 99% confidence interval for the mean commute time of all commuters in Washington D.C. area is between 22.7994 minutes and 33.1406 minutes. The interpretation is that we are 99% sure that the true mean ommute time of all commuters in Washington D.C. area is between 22.7994 minutes and 33.1406 minutes.