10.12 College debt versus adjusted in-state costs. Kiplinger’s “Best Values in Public Colleges’’ provides a ranking of U.S. public colleges based on a combination of various measures of academics and affordability.5 Let’s focus on the relationship between the average debt in dollars at graduation (AveDebt) and the in-state cost per year after need-based aid (InCostAid). A scatterplot with least-squares regression line is shown in Figure 10.12 for a sample of 25 colleges from Kiplinger’s 2015 report.

  1. (a) Does a linear relationship between InCostAid and AveDebt seem reasonable? Explain your answer.

  2. (b) Are there any unusual cases in this sample? If yes, state which ones they are and how they may be affecting the least-squares model fit.