Predicting a categorical label or class for input data. It is task-driven supervised learning.
Predicting a continuous numerical value based on input features. It is task-driven supervised learning.
Grouping similar data points together without predefined labels. It is data-driven unsupervised learning.
Source: Peng J, Jury EC, Dönnes P, Ciurtin C. Machine Learning Techniques for Personalised Medicine Approaches in Immune-Mediated Chronic Inflammatory Diseases: Applications and Challenges. Front Pharmacol. 2021 Sep 30.