Lesson objective: Connect meaning of the slope and intercept to the line of best fit for a set of bivariate data.

This lesson provides an opportunity for students to apply their knowledge and understanding of a line of best fit to a real-life situation. Students are asked to find and interpret a line of best fit for walking and running around a track one time.

Key Concept students will use:

- Bivariate data may not have an exact linear association, but a linear model is often used to describe the association.

Skills students will use:

- two points to find the slope of a line (Grade 8, Unit 7)
- two points to find the equation a line (Grade 8, Unit 7)

Students engage in Mathematical Practice 5 (Use appropriate tools strategically) as they determine a line of best fit for a scatter plot and interpret the meaning of the slope and intercept in the context of the units of the problem.

**Key vocabulary: **

- intercept
- line of best fit
- negative association
- scatter plot
- rate of change
- slope
- y-intercept