FIX Several small fixes

python_scripts/01_tabular_data_exploration.py

@@ -364,5 +364,5 @@
 #   and evaluating your machine learning model;
 # * having redundant (or highly correlated) columns can be a problem for some
 #   machine learning algorithms;
-# * contrary to decision tree, linear models can only capture linear
-#   interactions, so be aware of non-linear relationships in your data.
+# * decision trees create rules at constant values of the features, such as
+#   vertical and horizontal lines in a 2-dimensional feature space.

python_scripts/cross_validation_learning_curve.py

@@ -104,7 +104,7 @@
 #
 # If we achieve a plateau and adding new samples in the training set does not
 # reduce the testing error, we might have reached the Bayes error rate using the
-# available model. Using a more complex model might be the only possibility to
+# available model. Using a more expressive model might be the only possibility to
 # reduce the testing error further.
 #
 # ## Summary