Ensembling in machine learning combines predictions from multiple models for creating powerful models, reducing variance, bias, and overfitting.
Bagging stabilizes ML models by reducing variance, creating an ensemble of models by bootstrapping the dataset, training models, and averaging or majority voting predictions.
Bagging works well for high-variance models like decision trees, improving model robustness to data fluctuations and spurious relationships.
A bagging example demonstrates how averaging predictions from multiple trees can reduce variance and improve model accuracy.
Boosting reduces bias by sequentially training models to correct predictions of previous models, enhancing predictions and model performance.
Boosting iteratively improves predictions by updating residual predictions or adding more weight to poor predictions, reducing bias and potentially variance.
Important parameters in boosting include the number of trees, tree depth, and learning rate, which affect model performance and overfitting.
Boosting uses a learning rate to discount residual predictions, mitigating overfitting and balancing the influence of individual trees in the ensemble.
Bagging and boosting have distinct characteristics: bagging focuses on reducing variance while boosting aims to reduce bias in weak learners.
In practice, bagging and boosting are usually implemented using advanced algorithms that enhance the basic concepts for improved model performance.
Ensembling techniques like bagging and boosting are valuable tools for data scientists to enhance model accuracy and generalization across various machine learning applications.