Evaluate a random forest model

Similar to the linear regression model, you will use the MAE metric to evaluate the performance of the random forest model.

100 XP

Calculate the MAE by comparing the actual with the predicted values for the validate data and assign it to the validate_mae column.
Print the validate_mae column (note how they vary).
Calculate the mean of this column.

Note: The actual values of the validate fold (validate_actual) has already been added to your cv_data data frame.