A decision-making process we conduct in our heads.
A model in which graphics or diagrams are used to convey real objects or situations. Examples are a map or a graph.
A number of different types of models exist. The most common are mental models, which we “build” in our heads and use to make decisions. The traffic-light situation calls for a mental model. Visual models use graphics or diagrams to represent real objects or situations. For example, a road atlas represents a system of roads and other key land features. Physical models involve objects that represent other objects, such as an architect's scale model of a new building. Mathematical models use equations and relationships among quantities to represent situations. Many of the concepts in this textbook are shown through the use of mathematical models. Spreadsheet models are a means of implementing mathematical models.
Although there are a number of different model types, commonalities exist among them. First, the use of models is motivated by a decision that needs to be made, for example, whether to stop or go at a yellow light or how much of a product to order at one time. Second, all models rely on inputs. Inputs are quantities or factors that affect the situation. Inputs can be controllable ...