Illustration of the model selection process, which consists of identifying the 2 classes of ML. (A) In supervised learning method, after the hyperparameter tuning, data can be applied to 2 different tasks: classification or regression, depending on the type of the outcome. If the outcome is a category, then classification can be performed, whereas if the outcome variable is a numeric value, regression may be applied for prediction. (B) Unsupervised learning, the data in which the data are either used for clustering, topical modeling, or representing the data distribution while reducing the dimensionality of the data according to the problem to be solved. ML = machine learning.