La compromis biais-variance is a key concept in apprentissage automatique and modélisation statistique that addresses the trade-off between two types of errors that affect the performance of predictive models: bias et variance.
Biais refers to the error introduced by approximating a real-world problem, which may be complex, with a simplified model. High bias can cause an algorithm to miss relevant relations between features and target outputs—this is known as underfitting. Underfitting occurs when a model is too simple to capture the underlying patterns in the data.
Variance, on the other hand, refers to the model’s sensitivity to fluctuations in the données d'entraînement. High variance can cause an algorithm to model the random noise in the training data rather than the intended outputs—this is known as overfitting. Overfitting occurs when a model is too complex and captures noise rather than the actual signal.
The tradeoff is that as you increase the complexity of your model to reduce bias, you may increase variance, and vice versa. The goal in la formation de modèles is to find a balance between bias and variance that minimizes the overall error when the model is applied to unseen data.
This balance is often visualized using a U-shaped curve, where the x-axis represents la complexité du modèle and the y-axis represents error. The lowest point on the curve indicates the optimal level of complexity that achieves the best predictive performance.