Which of the following is a hyperparameter in boosting algorithms?Review LaterLearning rateNumber of estimatorsMaximum depthSubsample size

All of the options you provided are hyperparameters in boosting algorithms. Here's a brief explanation of each:

1. Learning Rate: This is a tuning parameter in an optimization algorithm that determines the step size at each iteration while moving toward a minimum of a loss function. In boosting, it shrinks the contribution of each classifier.

2. Number of Estimators: This is the number of sequential trees to be modeled. While adding more trees can significantly improve accuracy, it can also make the model complex and result in overfitting.

3. Maximum Depth: This is the maximum depth of the individual regression estimators. The maximum depth limits the number of nodes in the tree. The best value depends on the interaction of the input variables.

4. Subsample Size: This is the fraction of samples to be used for fitting the individual base learners. If smaller than 1.0 this results in Stochastic Gradient Boosting. Subsampling allows the model to generalize better and avoid overfitting.