A positive statement is one that seeks to describe the world as it is. The first and third statements fall into this category.

A normative statement is one that offers an opinion as to the way the world should be. The second and fourth statements fall into this category.

Note that describing a statement as positive or normative is not the same as describing it as true or false. Positive statements may be false (for example, “You are the king of Spain”), and normative statements may reflect the value judgments of a large majority of people (for example, “It is wrong to kill innocent children”). However, positive statements can always be supported or refuted by data, while normative statements require a larger philosophical framework to evaluate. It's quite easy to prove that you are not the king of Spain, but to argue that it is wrong to kill innocent children, you must appeal to a larger moral framework. Such a framework is based on values and cannot be confirmed or refuted by evidence.