Classification problem

• Predict a discrete valued output (yes/no) or (A, B, C, D)

• Brest Cancer: Tumor size (x) vs being malignant or benign (y) - two distinct possibilities. Given a tumor (and its size) what is the probability that it is malignant?

• The Tumor size is a "feature". In other problems we might have many more features.

• e.g. We might know both the tumor size and the age of the patient.