Lesson 7

The mathematical purpose of this lesson is for students to find and interpret the correlation coefficient, and to use it to understand the strength of a linear relationship. The term correlation coefficient is introduced and is defined as a number that can be used to determine how well a line models the data. The work of this lesson connects to previous work because students plotted and analyzed residuals to informally assess the fit of linear models. The work of this lesson connects to upcoming work because students will use technology to compute the correlation coefficient and use it to describe the relationship between two variables.

When students sorted scatter plots, they were given the opportunity to analyze representations, statements, and structures closely and make connections (MP2, MP7). When students take turns with a partner, matching graphs of residuals to scatter plots that display linear models with the correlation coefficient, students trade roles explaining their thinking and listening, providing opportunities to explain their reasoning and critique the reasoning of others (MP3).

Print and cut up slips from the blackline master for the card sort activity. One copy is needed for every group of 2 students.