ABSTRACT
Variables are not something that people only think about after gathering data, when they begin their analysis. On the contrary, the entire research study is typically designed because people have a theory-based idea about how one variable affects another, and people want to gather and analyse data in order to find out more about this. Usually, educational researchers don’t study just one pupil—they take multiple measurements, perhaps from a whole class, or from several. This can allow them to compare the class under different conditions. If a variable is not kept constant, and instead affects one condition of the experiment more than the other, then it is known as a confounding variable. The null hypothesis states some kind of a baseline assumption—it is what can be assumed if the effect or interaction people are investigating does not occur. It could be based on prior, well-established research findings or a theory that is widely accepted.
