Machine Learning for OpenCV 4 - Second Edition

Scoring regressors using mean squared error, explained variance, and R squared

When it comes to regression models, our metrics, as shown earlier, don't work anymore. After all, we are now predicting continuous output values, not distinct classification labels. Fortunately, scikit-learn provides some other useful scoring functions:

• mean_squared_error: The most commonly used error metric for regression problems is to measure the squared error between the predicted and the true target value for every data point in the training set, averaged across all of the data points.
• explained_variance_score: A more sophisticated metric is to measure to what degree a model can explain the variation or dispersion of the test data. Often, the amount of explained ...