The table lists the average annual cost (in dollars) of tuition and fees at private 4 -year colleges for selected years.
(a) Determine a function defined by $f(x)=m x+b$ that models the data, where $x=0$ represents $1994, x=1$ represents $1995,$ and so on. Use the points $(0,11,719)$ and $(12,22,218) .$ Graph $f$ and a scatter diagram of the data on the same coordinate axes. (You may wish to use a graphing calculator.) What does the slope of the graph of $f$ indicate?
(b) Use this function to approximate tuition and fees in $2005 .$ Compare your approximation to the actual value of $\$ 20,980$
(c) Use the linear regression feature of a graphing calculator to find the equation of the line of best fit.
(TABLE CANNOT COPY)