Third, the infer workflow is much simpler for conducting inference when you have more than one variable. We’ll see two such situations. We’ll first see situations of two-sample inference where the sample data is collected from two groups, such as in Section 8.6 where we study the contagiousness of yawning and in Section 9.1 where we compare promotion rates of two groups at banks in the 1970s. Then in Section 10.4, we’ll see situations of inference for regression using the regression models you fit in Chapter 5.