Chapter 10, Problem 27E

To determine

To construct: the linear model for this relationship and disclosing any problems that the model might have.

Explanation of Solution

Given:

speed (mph)	Fuel eff. (mpg)
35	25.9
40	27.7
45	28.5
50	29.5
55	29.2
60	27.4
65	26.4
70	24.2
75	22.8

Graph:

Scatter Plot:

  

Residual plot:

  

Data analysis

Data > Data analysis > Regression

Step 1. Enter data in excel spreadsheet

Step 2. Click on Data > Data analysis > Regression.

Step 3. Select input Y and X range

Step 4. Click Ok

This is the obtained output

  

The regression from this output given as

  $Fuelefficiency=-0.0973Speed+32.198$ and R-squared value is 34.81%. from the above plot it can said that there is too much bend or curvature in the line. Therefore, the relationship could not be happened straight by this method.