# Question

The following data show the costs charged by a tax preparation service for a random sample of 15 tax returns. These data can also be found in the Excel file titled tax prep costs. xlsx.

a. Using a 98% confidence interval, estimate the average cost of the service for preparing a tax return for a customer.

b. What is the margin of error for this sample?

c. Verify your result using Excel.

d. What assumptions are necessary for this analysis?

a. Using a 98% confidence interval, estimate the average cost of the service for preparing a tax return for a customer.

b. What is the margin of error for this sample?

c. Verify your result using Excel.

d. What assumptions are necessary for this analysis?

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