How do we determine if data in a table represents a function?

If each input value has one and only one output value, the data in the table represents a function.

Step-by-step explanation:

It is important to remember that, by definiton, a relation is a function if each input value (or x value) has one and only one output value (or y value).

Therefore, to determine if a data in a table represents a function, you must see if each value of "x" in the table has an unique value of "y".

An example of data in a table that represents a function is shown in the image attached.