Bringing it all together
• Describe how two quantitative variables are related. • Use technology to create a line of best fit. • Fit a line to given data and use it to make predictions. • Interpret the coefficients of a line of best fit in the context of the data to which it is fitted. • Compute and interpret a correlation coefficient. • Understand that variables with a high correlation do not necessarily have a causal relationship.
In this unit, students build on the statistical work they did in grade 8. Using technology, they represent data on two variables on a scatter plot, find the line of best fit, and interpret the slope and intercepts in context. They assess the fit of a line to data more precisely by plotting and analyzing residuals. Students compare strength of associations between different pairs of variables by interpreting correlation coefficients which they compute using technology. They gain experience in distinguishing between correlation and causality. Modeling is an intrinsic part of the high school statistics and probability standards and of this unit.