91Ó°ÊÓ

A scatter plot is a kind of plot where we use Cartesian coordinates to display values for typically two variables for a set of data.

Consider speed as x coordinate and calories as y coordinates.

The required plot is shown below:

The given data can be used to write a linear equation that approximate the number of calories burned per hour.

The point slope form is $y-y_1=\frac{y_2-y_1}{x_2-x_1}(x-x_1)$

Substitute $\left(x_1{y}_1\right)=(5,508)  and  \left(x_2{y}_2\right)= (8,858)$ into the above formula.

$\begin{array}{l}y−508=\frac{858−508}{8−5}(x−5)\\ y−508=116.67(x−5)\\ y−508=116.67x−583.35\\ y=116.67x−75.35\end{array}$

We need to determine the calories burned in an hour by a 140-pound person running at 9 miles per hours.

Put 9 for x into $y=116.67x-75.35$

$\begin{array}{l}y=116.67\left(9\right)−75.35\\ y=1050.03−75.35\\ y≈975\end{array}$

The model predicts that 140-pound person running at 9 miles per hour will burn 975 calories.

The actual value is 953. The predicted value differs from the actual value by 2% only.