Model

The model is the function that will be used to interpolate predictions for factor settings between the factor settings at which you collected data. The model is also referred to as the Prediction Equation.

The DOE concept is to “run a few and predict the rest”. This is the way you save time and money. Run a few experiments, as few as you can and still get sufficiently precise predictions of the rest by interpolation.

The “experiment design” is the list of the few that you run. The model is a formula, a mathematical function, that is fitted to the data so that you can “predict the rest”.