The Median Age of Vehicles on U. S. roads for seven different years.

Median Age in Years

Cars, x

8.1
7.7
6.5
6.9
6.0
5.4
4.9

Trucks, y

7.8
7.6
6.5
7.6
6.3
5.8
5.9

1) Find the centroid (x-bar, y-bar)

2) Find the regression line (y-hat)

3) Find the coefficient of determination, what can you conclude?

4) Find the standard error of estimate

5) Construct a 95% prediction interval for the median age of trucks in use when the median age of cars in use is 7.3.

6) Find the a) explained variation, b) unexplained variation, and c) total variation