A hypothesis is a proposition about how you expect something to work. You can observe a phenomenon and try to explain it or you can try to predict what sort of phenomenon will occur in a given set of circumstances. The question that you are posing here seems to be of the second variety. Therefore, what you need to do is to try to predict something that you think will be true of how people handle romantic relationships on Facebook. It will be hard for us to give you a really good hypothesis here because it is not exactly clear as to what you mean by “handle relationships.”
One likely way to approach this would be to hypothesize that different types of people will handle relationships differently on Facebook. You might divide people up into men and women, older people and younger people, or some other division. You will then predict how you believe that these groups will differ in their handling of relationships on Facebook.
So, possible hypotheses might be:
- People in high school and junior high are likely to expose more of their personal relationships on Facebook than older people are.
- High school-age girls are more likely than high school-age boys to talk about their romantic relationships on Facebook.
These are hypotheses that you can then go on to test.