This is a two-week instructional unit for Grades 9-12 on data analysis. Students use real-life data to interpret the slope and y-intercept of least squares regression lines in the context of everyday situations. Lessons include travel distances, bathtub water levels, and automobile age vs. mileage. In each activity, students interpret the meaning of slope and y-intercept, calculate correlation coefficients, and fit the data by estimating parameters. Individual lessons can be easily parsed out to create a shorter unit.