Choose a data set of fuel prices from the attached Excel file.
Find the mean and standard deviation for the data set. Please do not try to do this by hand, but use the functions in Excel.
Find the 95% Confidence Interval for your data.
Response Post Instructions:
Respond to two of your classmates by analyzing what the confidence interval means in this scenario and how this data can be used. And then compare how the results vary between the different data sets.
Sample initial post:
First find the mean and standard deviation. (Refer to video in week 2 discussion.)
Then type this in an excel cell =confidence.norm(0.05,stdev,samplesize) and hit enter. This is the E value. (Note: please use your standard deviation and sample size and not the words.)
Set up your confidence interval: (mean-E, mean+E)
It is important to go back and read follow up responses from your instructor.
Formula you used above for the confidence interval:
The formula is E= zsubc * sigma / sqrt n
Where the left hand endpoint is xbar – E and the right hand endpoint is xbar + E