Here are some examples of areas of interest, research questions that may emerge and how an hypothesis may be written. Remember that these aren't the ONLY research questions or hypotheses that you could use in each case, they're just examples:
Notice that in every example, the Hypothesis is phrased in a negative sense - that is, that whatever the area of interest, it makes no difference to the dependent variable - that is, the one that is being counted or measured. This is common practice in research and when the principle hypothesis is phrased in this way it is known as the Null Hypothesis and this is important.