63. Cost of Private College Education The table lists average annual cost (in dollars) of tuition and fees at private four-year colleges for selected years. Year 2013 2014 2015 2016 2017 Data from National Center for Education Statistics. Cost (in dollars) 24,523 25.707 26,739 27,942 29,478 a. Determine a linear function f(x) = ax + b that models the data, where x = 0 represents 2013, x = 1 represents 2014, and so on. Use the points (0, 24,523) and (4, 29,478) to graph f and a scatter diagram of the data on the same coordinate axes. What does the slope of the graph indicate? b. Use the function from part (a) to approximate average tuition and fees, to the nearest dollar, in 2016. Compare the approximation to the actual figure given in the table, $27,942. c. [A graphing calculator is required.] Use the linear regression feature of a graphing calculator to find the equation of the line of best fit.