A real estate agent has collected a random sample of 75 houses that were recently sold in a suburban community. She is particularly interested in comparing the appraised value and recent selling price of the houses in this particular market. The data are provided in the file P08_24.xlsx. Using this sample data, find a 95% confidence interval for the mean difference between the appraised values and selling prices of the houses sold in this suburban community. Interpret the confidence interval for the real estate agent.