Chapter 9, Problem 32E

(a)

To determine

To make a scatterplot of average speed against year and describe the relationship of average speed by year, being careful to point out any unusual features in the plot.

Explanation of Solution

Now, by the Tour de data in the second chapter we are making the scatterplot as:

  

In this the average speed in on the vertical axis and the years on the horizontal axis. We can see in the scatterplot that there are two clusters of points that does not seem show much correlation and it can be because of the years mentioned in the data.

(b)

To determine

To find the regression equation of average speed on year.

Answer to Problem 32E

  $\text{<mover accent="true"><mo>A</mo><mo>^</mo></mover> verage speed}=-254.73+0.1473\times \text{Years}$ .

Explanation of Solution

The tour de France data is used in the question to find the relationship between the average speed against the years. Thus, in part (a) the scatterplot has been created which shoes the association between the average speed and the years. Also, in the scatterplot the regression line has been calculated, which is as:

  $\text{<mover accent="true"><mo>A</mo><mo>^</mo></mover> verage speed}=-254.73+0.1473\times \text{Years}$ .

(c)

To determine

To comment are the conditions of regression met or not.

Explanation of Solution

The tour de France data has been used in the question to find the relationship between the average speed against the years. Thus, in part (a) the scatterplot has been created which shoes the association between the average speed and the years. Now, as we can see that the requirements of the regression are not met because the large cluster around the year $\text{2000}$ shows no correlation and the pattern of the data does not seems linear.