In supervised machine learning what's the difference between training data and test data? Select an answer: Training data is the data the machine uses to learn, test data is a sample of data to test what it learned. Training data is all the data that the system can gather, then the test data is a small sample used for training. Test data is where all the learning takes place before it trains on a large sample of the data. There isn't a difference, you can mix and match training and test data