Unit 2: Two-Variable Relationships Main Concepts | Demonstration | Teaching Tips | Data Analysis & Activity | Practice Questions | Connections | Fathom Tutorial | Milestone
 Connections • Exploratory Data Analysis Like the last unit, this unit provides tools to answer questions about the relationships between two numerical variables in a given data set using numerical and graphical summaries. As discussed in Unit 1, correct interpretation of the summaries and the model outputs are key. In this unit, students must especially be aware of how to do this for transformed variables. But in general, students should be aware of the variables and observational units in question. As discussed in the previous unit, later in the course, we will learn to determine if apparent linear associations might be due to chance just as we would like to determine whether differences between groups (as covered in Unit 1) are due to chance. • Models This unit continues the discussion of statistical models and specifically discusses in more detail the idea of model selection. Like in the last unit, students will have trouble with this abstractness of theoretical models and, in this unit, particularly with the idea of interpreting models in the context of transformed or aggregate variables. As mentioned in the last unit, introducing this early might help alleviate that confusion for upcoming units dealing with probability and simulation models.