Alpha is a hyperparameter that is used while changing the weights of the samples in an AdaBoost model.

Which of the following statement(s) is/are correct?

A) The weight of a sample is decreased if it is incorrectly classified by the previous weak learner.
B) The weight of a sample is increased if it is incorrectly classified by the previous weak learner.
C) The alpha can be both positive or negative
D) The alpha cannot be negative