Steps in validating a test
Successively, the fitted model is used to predict the responses for the observations in a second dataset called the validation dataset.
This simple procedure is complicated in practice by the fact that the validation dataset's error may fluctuate during training, producing multiple local minima.
through building a mathematical model from input data.
Most approaches that search through training data for empirical relationships tend to overfit the data, meaning that they can identify and exploit apparent relationships in the training data that do not hold in general.In particular, three data sets are commonly used in different stages of the creation of the model.