📝 Exercise M5.02

The aim of this exercise is to find out whether a decision tree model is able to extrapolate.

By extrapolation, we refer to values predicted by a model outside of the range of feature values seen during the training.

We first load the regression data.

import pandas as pd

penguins = pd.read_csv("../datasets/penguins_regression.csv")

feature_name = "Flipper Length (mm)"
target_name = "Body Mass (g)"
data_train, target_train = penguins[[feature_name]], penguins[target_name]

Note

If you want a deeper overview regarding this dataset, you can refer to the Appendix - Datasets description section at the end of this MOOC.

First, create two models, a linear regression model and a decision tree regression model, and fit them on the training data. Limit the depth at 3 levels for the decision tree.

# Write your code here.

Create a synthetic dataset containing all possible flipper length from the minimum to the maximum of the training dataset. Get the predictions of each model using this dataset.

# Write your code here.

Create a scatter plot containing the training samples and superimpose the predictions of both models on the top.

# Write your code here.

Now, we check the extrapolation capabilities of each model. Create a dataset containing a broader range of values than your previous dataset, in other words, add values below and above the minimum and the maximum of the flipper length seen during training.

# Write your code here.

Finally, make predictions with both models on this new interval of data. Repeat the plotting of the previous exercise.

# Write your code here.