Exercise

Evaluate the 10-fold CV error

In this exercise, you'll evaluate the 10-fold CV Root Mean Squared Error (RMSE) achieved by the regression tree dt that you instantiated in the previous exercise.

In addition to dt, the training data including X_train and y_train are available in your workspace. We also imported cross_val_score from sklearn.model_selection.

Note that since cross_val_score has only the option of evaluating the negative MSEs, its output should be multiplied by negative one to obtain the MSEs.

Instructions

100 XP

Compute dt's 10-fold cross-validated MSE by setting the scoring argument to 'neg_mean_squared_error'.
Compute RMSE from the obtained MSE scores.

Take Hint (-30 XP)