Question: Mortgage lenders often use FICO® scores to check the credit worthiness of consumers applying for real estate loans. In general, FICO scores range between 300 and 850 with higher scores representing a better credit profile. A lender in a Midwestern town would like to estimate the mean credit score of its residents. What is the required number of sample FICO scores needed if the lender does not want the margin of error to exceed 20, with 95% confidence?