Sunk Costs are costs that have been paid and cannot be recovered.
A rational decision benefits the decision maker as much as possible.
A self-interested individual makes decisions for his or her benefit
Wearing a seat belt is an example of a rational decision
The net benefit of a choice is the benefit minus the cost in dollars.
Marginal benefit is the additional benefit doing something one more time.
** Marginal cost** is the additional cost of doing something one more time.
Marginal analysis -- Decision making process by comparing marginal cost and benefits