The research question is the question that you hope to answer with your survey of resources, experiment or study. As noted elsewhere in this libguide, the author should be careful that their research question does not have too narrow or too broad of a scope.
A well written research question will then help you construct a hypothesis. The purpose of the hypothesis is to manipulate variables related to the subject to attempt to answer your research question. In this way, the hypothesis and research question are closely related.
In order to have a successful research question and hypothesis, it must be something that is testable and gives scientifically measurable results. The data from these tests will allow you to answer your research question. Too often, hypotheses are constructed that lead to experiments that are not easily measurable, making it difficult to answer your research question definitively.