Answer:
Confidence =
And then the confidence level would be given by 99%
Step-by-step explanation:
The margin of error is the range of values below and above the sample statistic in a confidence interval.
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
Assuming the X follows a normal distribution
The distribution for the sample mean is given by:
represent the sample mean
represent the population standard deviation
n= 100 sample size selected.
The confidence interval is given by this formula:
(1)
The marginof error for this case is given by Me=25.76. And we know that the formula for the margin of error is given by:
And we can find the critical value like this:
And we know that on the right tail of the z score =2.576 we have of the total area. We can find the area on the right of the z score using this excel code:
"=1-NORM.DIST(2.576,0,1,TRUE)" or using a table of the normal standard distribution, and we got 0.004998=, so then
, and then we can find the confidence like this:
Confidence =
And then the confidence level would be given by 99%