8.48 Evaluate the model

Collect metrics using augment

augment(reg_tree_fit, new_data = carseats_train) %>%
  rmse(truth = Sales, estimate = .pred)

## # A tibble: 1 × 3
##   .metric .estimator .estimate
##   <chr>   <chr>          <dbl>
## 1 rmse    standard        1.58

augment(reg_tree_fit, new_data = carseats_test) %>%
  rmse(truth = Sales, estimate = .pred)

## # A tibble: 1 × 3
##   .metric .estimator .estimate
##   <chr>   <chr>          <dbl>
## 1 rmse    standard        2.18

Training RMSE: 1.58 Testing RMSE: 2.18 (overfit)