Update notebook based on reviewer's comments

cbs_with_qrf.ipynb

data/error_estimates_qrf/aims_X_test.csv

data/error_estimates_qrf/aims_X_train.csv

data/error_estimates_qrf/aims_y_test.csv

data/error_estimates_qrf/aims_y_train.csv

data/error_estimates_qrf/exciting_X_test.csv

data/error_estimates_qrf/exciting_X_train.csv

data/error_estimates_qrf/exciting_y_test.csv

data/error_estimates_qrf/exciting_y_train.csv

...or_estimates_qrf/sisso_aims_trained_model_predictions.csv

...stimates_qrf/sisso_exciting_trained_model_predictions.csv