Final answer:
A table represents a function if each input has exactly one output. Positive or negative values or the data being integers are unrelated to the table being a function. The correct answer is that the table represents a function because each input corresponds to one output.
Step-by-step explanation:
To determine whether the table represents a function, we must evaluate the relationship between the inputs and outputs. A function requires that for every input, there is exactly one output associated with it. Having inputs with multiple outputs or the nature of the output values (positive or negative) doesn't affect whether it's a function or not.
Option d) correctly describes when a table does not represent a function, which is when an input has more than one output. This would violate the definition of a function. The examples of economic models using functions, such as Professor = Adam Smith or the export and import functions with horizontal lines, emphasize that functions describe relationships.
Lastly, the table provided with points (1,5), (2,10), (3,7), and (4,14) shows a different output for each input, which supports that the table does represent a function. The dependence of y on x is shown by these points, and they can be plotted on a graph to visualize the relationship.