HW #11 - Additional Question #1

A: Download the Tips Dataset and fit a simple linear regression model to predict “Tip” using “TotBill”. Provide an interpretation of the slope and intercept of this model.

B: Add the categorical predictor “Sex” to the model described in Part A. Using this model, do males or females appear to be more generous tippers?

C: In Part B you made a determination that either males or females tended to give higher tips. Could “TotBill” be a confounding variable in this scenario? Briefly explain. (Hint: think about the model you used in Part B)

D: Use Forward Selection (with \(\alpha = 0.10\) as the entry criteria) to select a model. Which variables were selected in this model? What are the \(R^2\) and adjusted \(R^2\) of this model?