Chapter 9, Problem 34E

(a)

To determine

To find the regression of average speed by year only for years from $1947$ to the present and are the conditions for regression met.

Explanation of Solution

In this question, we will be using the data of Tour de France from $1947$ to the present. Then we will have the following scatterplot:

  

And in this the regression line is given by:

  $\text{<mover accent="true"><mo>A ^</mo></mover> verage speed}=-35.208+0.0377\times \text{Years}$

And the also $R^2=2.31\%$ is given in the scatterplot. It explains that the variations explained by the variable of the data. So, we have that $2.31\%$ is explained by the average speed over the years. The regression conditions are met because it is not showing any clusters and the data is scatter normally.

(b)

To determine

To interpret the slope.

Explanation of Solution

In this question, we will be using the data of Tour de France from $1947$ to the present.And in this the regression line is given by:

  $\text{<mover accent="true"><mo>A ^</mo></mover> verage speed}=-35.208+0.0377\times \text{Years}$

And the also $R^2=2.31\%$ is given in the scatterplot. It explains that on average the average speed is increasing by $0.0377$ per year.

(c)

To determine

To explain which was the most remarkable performance.

Answer to Problem 34E

The most remarkable performance was of the Lance Armstrong.

Explanation of Solution

In this question, we will be using the data of Tour de France from $1947$ to the present. And in this the regression line is given by:

  $\text{<mover accent="true"><mo>A ^</mo></mover> verage speed}=-35.208+0.0377\times \text{Years}$

And the also $R^2=2.31\%$ is given in the scatterplot. $\text{In 1979, Bernard Hinault averaged 39}\text{.8 kph}$

  $\text{while in 2005, Lance Armstrong averaged 41}\text{.65 kph}$ . Then, the most remarkable performance was of the Lance Armstrong because his average speed was more than the Bernard. Thus, he was a better perform by his average speed.