# Lesson 5

Goodness of Fit

These materials, when encountered before Algebra 1, Unit 3, Lesson 5 support success in that lesson.

### Lesson Narrative

The mathematical purpose of this lesson is for students to understand what makes a linear model a better or worse fit for data displayed using a scatter plot. In the associated Algebra 1 lesson, students create lines of best fit and interpret the \(y\)-intercept of a linear model in terms of the situation. Students construct viable arguments (MP3) when they explain the goodness of fit of lines created using various methods.

### Learning Goals

Teacher Facing

- Understand what makes a linear model a better or worse fit for data

### Student Facing

- Let’s explore lines and their goodness of fit for data