1. Sullivan Algebra and Trigonometry: Section 2.5 Objectives Draw and Interpret Scatter Diagrams Distinguish between Linear and Nonlinear Relations Find an Equation for Linearly Related Data

2. The data below represents the price per gallon of gasoline in 1994 and the average number of miles driven per auto for various countries. Source: Energy Information Administration

3. To determine if a relationship exists between the two variables, we plot the points on the xy-plane. The resulting plot is called a scatter diagram. This plot shows a linear relationship.

4. Linear Relationships Non-Linear Relationships

5. Example: Find the equation of a line describing the data set in the first example, describing gas mileage. First, select two point from the data set. (1.57,10,371) and (3.44,7456) Now, use these two points to find a linear equation as shown in section 2.3. Let (x 1,y 1 ) = (1.57,10,371)

6. The graph of the data and the line found is