Adjusting the regularization strength

Your current Lasso model has an \(R^2\) score of 84.7%. When a model applies overly powerful regularization it can suffer from high bias, hurting its predictive power.

Let's improve the balance between predictive power and model simplicity by tweaking the alpha parameter.

This exercise is part of the course

Dimensionality Reduction in Python

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Exercise instructions

Find the highest value for alpha that gives an \(R^2\) value above 98% from the options: 1, 0.5, 0.1, and 0.01.

Hands-on interactive exercise

Have a go at this exercise by completing this sample code.

# Find the highest alpha value with R-squared above 98%
la = Lasso(____, random_state=0)

# Fits the model and calculates performance stats
la.fit(X_train_std, y_train)
r_squared = la.score(X_test_std, y_test)
n_ignored_features = sum(la.coef_ == 0)

# Print peformance stats 
print(f"The model can predict {r_squared:.1%} of the variance in the test set.")
print(f"{n_ignored_features} out of {len(la.coef_)} features were ignored.")

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