All practice problems from the unit. Unit: Alg1.3 Two-variable Statistics (Algebra 1). Alg1.3 Two-variable Statistics In grade 8, students informally constructed scatter plots and lines of fit, noticed linear patterns, and observed associations in categorical data using two-way tables. In this unit, students revisit two-way tables to find associations in categorical data using relative frequencies. The unit also builds on previous knowledge of scatter plots by assessing how well a linear model matches the data using residuals as well as the correlation coefficient for best-fit lines (found using technology). It closes with an exploration of the difference between correlation and