Initial Post: Assuming .05 as your alpha value, make up a problem similar to this one below. (Make up 36 gas prices for your example – be sure they are similar to the prices you have had in your area.) List the values in your post.
In your response, describe what you did and give the mean, standard deviation and confidence interval.
- First find the mean. List all 36 gas prices in cells A1 to A36 in your excel spreadsheet.
- On a different cell type in =average(A1:A36) and the hit enter to find the average
- Assume your answer is 2.65
- On a different cell type in =stdev.s(A1:A36) or =stdevA(A1:A36) and enter to find the standard deviation
- Assume your answer is .43
- Then type this in an excel cell =confidence(.05,.43,36) and hit enter. This is the E value
- So take the mean of 2.65 and you have (2.65-E, 2.65+E) for your confidence interval
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
The above is an example. Please come up with something similar. Keep the answer separate please