Please, attachONEExcel file with solutions toALLexercises for this assignment (you cannot submit a separate Excel file for each exercise - it should be one Excel file which contains solutions to all exercises!).

(please use a link to send the Excel file to me)

Banking fees have received much attention during the recent economic recession as banks look for ways to recover from crisis. A sample of 30 customers paid an average fee of $12.55 per month on their interest-bearing checking accounts. Assume the population standard deviation is $1.75.

1. What is the margin of error for the 95% confidence interval for the average fee in the population?

Use NORM.INV() or NORM.S.INV()

2. Construct a 95% confidence interval for the average fee.

3. How would the confidence interval change if the confidence level increased, for example, to 98%?