# Training data

> The subset of the dataset used to train a model. Traditionally, examples in the dataset are divided into the following three distinct subsets:[^1]

The subset of the [dataset](https://wiki.g15e.com/pages/Dataset%20(machine%20learning.txt)) used to train a [model](https://wiki.g15e.com/pages/Model%20(machine%20learning.txt)). Traditionally, [examples](https://wiki.g15e.com/pages/Example%20(machine%20learning.txt)) in the dataset are divided into the following three distinct subsets:[^1]

- a training set
- a [Validation set](https://wiki.g15e.com/pages/Validation%20set.txt)
- a [Test set](https://wiki.g15e.com/pages/Test%20set.txt)

Ideally, each example in the dataset should belong to only one of the preceding subsets. For example, a single example shouldn't belong to both the training set and the validation set.[^1]

## Footnotes

[^1]: https://developers.google.com/machine-learning/glossary#training-set