The sales, in billions of dollars, of Keller Overhead Door Inc. for 2009 to 2014 are:

a. Plot the data.
b. Determine the least squares trend equation.
c. Use the trend equation to calculate the points for 2011 and 2014. Plot them on the graph and draw the regression line.
d. Estimate the net sales for 2017.
e. By how much have sales increased (or decreased) per year on the average during theperiod?