Your dissertation hypothesis is the prediction statement based on the theory that you are researching in your study. Doctoral candidates test their hypotheses in their dissertations, their original research project that they write and defend in order to graduate. Here, you will learn about hypothesis types, writing and testing for your dissertation and hypothesis examples.

Types

In your dissertation, you may create a hypothesis based on your research that predicts a relationship, called an "alternative" or "research" hypothesis. To balance your findings, you will also create a "null" hypothesis, which claims that the relationship that is to be proven in the research hypothesis does not exist. According to Alan Agresti and Barbara Finlay in “Statistical Methods for the Social Sciences,” the null is directly tested and predicts no effect, and the alternative contradicts the null and predicts an effect.

There can also be types of research hypotheses. As indicated in Research Methods Knowledge Base, a "one-tailed" hypothesis specifies a direction, either an increase or a decrease, while a "two-tailed" hypothesis does not specify a direction, only a change.

Writing

You must write your dissertation hypotheses before you collect and analyze your data. A useful hypothesis as testable and should include the independent variable, which you control, and the dependent variable, which is observed or measured based on the independent variable. For example, taking media consumption of violence as the independent variable and aggression as the dependent variable, the null hypothesis could state, “Media consumption of violence has no effect on aggression,” while the alternative hypothesis would state, “Media consumption of violence has an effect on aggression.” Similarly, if you wanted to create a one-tailed hypothesis, you would indicate a direction, such as, “Media consumption of violence increases aggression." Make sure that your statements are brief and straight-to-the-point and keep in mind the results you will measure in your study.

Testing

Research Methods Knowledge Base states that hypothesis testing assumes that both mutually exclusive hypotheses (research and null) exhaust every possible outcome and in the end, one is accepted and the other is rejected. When you analyze your data, you conclude whether you reject your null hypothesis and accept your alternative or fail to reject your null.

Examples

A dissertation can test a very broad range of hypotheses, depending on the discipline and focus of the writer. For example Antoinette Hill from Our Lady of the Lake University lent her research hypothesis to the title of her dissertation, "Are There Differences in Leadership Styles at Local, State, and National/Federal Levels among Advocates for People with Disabilities?" Her hypothesis used leadership as the independent variable and level of advocacy for people with disabilities as the dependent variable. Simply looking through the titles of dissertations published at a university of college each year can provide a long list of examples of a variety of hypotheses and ways to present them.