Multiple choices questions in Machine learning. Interview questions on machine learning, quiz questions for data scientist answers explained, Exam questions in machine learning, ensemble learning, boosting, AdaBoost algorithm, how does AdaBoost make use of weak learners, how does boosting algorithm work?
Machine Learning MCQ - Differences between ensemble learning methods - bagging and boosting
1. The AdaBoost
algorithm creates an ensemble of weak classifiers. Before determining the next
weak classifier, which one of the following is done by the AdaBoost
algorithm?
a) Chooses a new
random subset of the training examples to use
b) Decreases the
weights of the training examples that were misclassified by the previous weak
classifier
c) Increases the weights of the training examples that were misclassified by the previous weak classifier
d) Removes the
training examples that were classified correctly by the previous weak
classifier
Answer: (c) Increases the weights of the training examples that
were misclassified by the previous weak classifier Boosting Boosting is an ensemble learning method which trains each new model such that it focuses on correcting the errors made by the previous model.Boosting uses homogeneous weak learners in sequential
manner to learn and tries to reduce bias on final predictions. Boosting ensemble
modeling works on the following principle. First, a model is built from the
training data. Then the second model is built which tries to correct the
errors present in the first model. This procedure is continued and models are
added until either the complete training data set is predicted correctly or
the maximum number of models have been added.
AdaBoost increases the weights of the training examples that were misclassified by the previous weak classifier before determining the next weak classifierAdaBoost or Adaptive Boosting is one of the
ensemble boosting classifier. It combines multiple weak classifiers to
increase the accuracy of classifiers.
AdaBoost fits a
sequence of weak learners on different weighted training data. It starts by
predicting the original data set and gives equal weight to each observation.
If prediction is incorrect using the first learner, then it gives higher
weight to observation which have been predicted incorrectly. Being an
iterative process, it continues to add learner(s) until a limit is reached in
the number of models or accuracy.
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Related links:
What is ensemble learning?
AdaBoost is a linear classifier
What is boosting?