This form also includes extended descriptions, such as surveys, and may include important research, both basic and applied. Clearly, we are more impressed with the ability to predict what will happen than the ability to describe what we all knew happened. This meta hypothesis is, or can be, in exactly the same form as hypothesis testing, but is seldom recognized as such. We can have more, but we must have this much. We can have propositions including many variables and many relationships, and we can add all sorts of conditions, but these more complex propositions are just combinations of simple propositions, so we will limit our discussion to the simplest case.
Men are taller than women.
Now, this is a simple assertion, and it is probably reasonably clear. If it doesn't take on more than one value, we have no way of testing an hypothesis concerning what happens if it varies. And this variation can be nominal, ordinal, interval or ratio. Do not worry if your initial proposition doesn't clearly describe your variables. For these students, there are two possibilities.