Middle Grades Math: Lines of Fit

Objectives

• Students will discover that straight lines are widely used to model relationships between two quantitative variables.
• Students will informally fit a straight line and assess the model fit by judging the closeness of the data points to the line for scatter plots that suggest a linear association.
• Students will reason abstractly and quantitatively.
• Students will construct viable arguments and critique the reasoning of others.

Vocabulary

• line of fit

About the Lesson

This lesson involves informally fitting a straight line for a given data set that represents mean verbal and mathematics scores on SAT in 2004 across all 50 states and Washington, D.C.
As a result, students will:

• Rotate and translate a line to fit a linear model to the scatter plot of the given data set.
• Discuss criteria for a good fit.
• Use the line of fit to make estimations and predictions.