High school graduates: The table on the following page shows the number, in millions, graduating from high school in the United States for selected years. a. Make a plot of the data and explain why a...

High school graduates: The table on the following page shows the number, in millions, graduating from high school in the United States for selected years.

a. Make a plot of the data and explain why a linear model is not appropriate.

b. Use regression to find a linear model for the years 1986 through 1991. (In this part and the next, round regression line parameters to three decimal places.)

c. Use regression to find a linear model for the years 1992 through 1998.

d. Write a formula for a model of the number, in millions, graduating as a piecewise-defined function using the linear models from part b and part c.

e. Make a graph of the formula you found in part d.

f. The number graduating in 1993 was 2.34 million. On the basis of your graph in part e, determine whether this is more or less than would be expected from your formula.