A hypothesis chapter must be included in any dissertation, to give a structure and direction to the research that is to follow. A hypothesis is an educated guess about the outcome of a research experiment made before the experiment is carried out. The hypothesis chapter is the section of the dissertation in which the hypothesis is stated and explained. The hypothesis chapter can be a part of the overall methodology section of the dissertation, or it can be a chapter unto itself, between the literature review and the methodology sections.
In order to form a hypothesis to describe in the hypothesis chapter, the student must review the literature. Reviewing the literature will give the student an idea of what is already known about the field and about the specific topic the student is researching. When the student sees the outcomes of similar studies on related topics, he or she will be able to formulate a hypothesis that can be the cornerstone of the hypothesis chapter and indeed of the dissertation itself.
It is not necessary that the hypothesis be stated in the hypothesis chapter, as long as it is an educated guess and is backed up by the research in the student's literature review. The hypothesis chapter will state the most likely outcome based on what is already known. If the hypothesis is disproved by the research, it is not necessary to go back and rewrite the hypothesis chapter. Having the hypothesis proven wrong is not a sign of failure. On the contrary, the research will be more intriguing when the hypothesis chapter is disproved, since the expected outcome did not take place.
There may be some confusion over the term "hypothesis chapter." Many people expect the hypothesis to be stated in the methodology chapter, the chapter in which the research methods are described. This is indeed the chapter which contains the hypothesis, so it is fair to call it the hypothesis chapter, but it is often referred to as a methodology chapter, since it also describes the research process that has been undertaken as well.