To determine how the number of approved mortgages is affected by mortgage interest rates (in %), an economist recorded the average mortgage interest rates and the numbers of approved mortgages in a large country for the past 10 years. The data are listed below. \"mammal a. Determine the least squares line for Y on X by showing all hand calculations. b. Interpret the coefcient estimates of the LS line in summarizing the relationship between mortgage interest rates and number of approved mortgages. c. Obtain an estimate of the average number of approved mortgages when the mortgage interest rate is 12.5%. Do you think this is a reliable estimate? Explain why or why not