Machine Learning Fundamentals › Training vs Testing Data

How does Training vs Testing Data work

Beginner

Answer

A dataset is usually split into a training portion, often seventy to eighty percent, and a testing portion, the remaining twenty to thirty percent. The model only sees the training data during learning and is evaluated afterward on the testing data.
Real-world example A bank builds a loan approval model on data from the last five years and tests it on the most recent six months of applications to see how it would have performed in practice.

Common follow-ups: What is a validation set, What is cross validation, What is overfitting