Question 10.79

10.79 Predicting college debt: Other measures.

Refer to Exercise 10.75. Let’s now look at AvgDebt and its relationship with all six measures available in the data set. In addition to the in-state cost after aid (InCostAid), we have the admittance rate (Admit), the four-year graduation rate (Grad), in-state cost before aid (InCost), out-of-state cost before aid (OutCost), and the out-of-state cost after aid (OutCostAid).

bestval

  1. Generate scatterplots of each explanatory variable and AvgDebt. Do all these relationships look linear? Describe what you see.
  2. Fit each of the explanatory variables separately and create a table that lists the explanatory variable, model standard deviation , and the -value for the test of a linear association.
  3. Which variable appears to be the best single explanatory variable of average debt? Explain your answer.

10.79

  1. Only InCostAid, Grad, and maybe InCost look linear.
  2. Variable -value
    InCostAid 3349.8 0.0001
    Admit 4092.0 0.8408
    Grad 3611.2 0.0021
    InCost 3797.0 0.0174
    OutCost 4056.1 0.4022
    OutCostAid 3977.8 0.1413
  3. InCostAid is the single best explanatory variable; it has the most significant -value and the smallest model standard deviation .