Use tree-based regression to predict re78 in the data frame nswpsid1 that is in the DAAG package. Compare the predictions with the multiple regression predictions in Chapter 6. Copy down the email...

Use tree-based regression to predict re78 in the data frame nswpsid1 that is in the DAAG package. Compare the predictions with the multiple regression predictions in Chapter 6.

Copy down the email spam data set from the web site given at the start of Section 11.2. Carry out a tree-based regression using all 57 available explanatory variables. Determine the change in the cross-validation estimate of predictive accuracy.