The mathematical purpose of this lesson is for students to understand that correlation coefficients describe the relationship between variables and the trend they create on a graph. Previously, students learned about lines of best fit and they distinguished between information given by a linear model and actual data. In the associated Algebra 1 lesson, students find and interpret correlation coefficients. Students practice an aspect of mathematical modeling (MP4) when they assess whether a data set is well modeled by a linear function. Students also reason abstractly and quantitatively (MP2) as they practice translating between a line of best fit and a context.