Errors and residuals

Errors and residuals are related to mathematical models. A mathematical model shows the relationships between different values and how they affect each other. Errors and residuals measure how accurate the mathematical model is at predicting the real world.

An Error is how much the model "got wrong" when it made a prediction. For example, if the model predicted something would happen and it didn't, then that is an error.

A Residual is how much the model "got wrong" when it made the prediction, but on a smaller scale. For example, if the model predicted that something would happen, but it was a little bit different to what actually happened, then that is a residual. It was close, but not quite exact.