Research literature on the topic you are interested in to come up with ideas for your hypothesis. A literature review is needed to provide background and theoretical basis for your hypothesis. Unless you are researching something completely new, your hypothesis should be grounded on existing research that supports a possible relationship between two variables that you want to research further. A hypothesis is a statement that predicts a relationship which you will test to determine if your research supports or rejects the prediction.
Ask yourself questions that come to mind based on the literature you review. While these questions you formulate are not a testable statement yet, they allow you to explore your interests and think about the variables and relationships you find. Pay attention to any correlations you find between variables. This will help you form your hypothesis statement.
Identify which variable is independent and which one is dependent. A hypothesis requires a relationship between two variables where the direction of the relationship determines which variable is independent and which one is dependent. The dependent variable is manipulated by the independent variable. For example, if you are testing the relationship between stress and heart attacks, where stress is the independent variable and heart attacks are the dependent variable, then the direction of the relationship would suggest that stress causes or does not cause heart attacks.
Write the hypothesis statement. There are different styles for writing a hypothesis. A Research Hypothesis is worded using the style of "if and then." An example of this would be, "If stress increases the rate of heart attacks, then people exposed to high levels of stress have more heart attacks." There are alternatives to the research hypothesis style, which is often used in dissertations. A null hypothesis statement is written on the basis of a relationship leading to no difference. An example of this is, "There is no difference in heart attack rates for people with high and low stress levels." The alternative hypothesis, or literary alternative, is used if you expect a difference. An example of this is, "high stress individuals will have more heart attacks than low stress individuals."
Reread your hypothesis statement several times and ask peers to read it. It is really important that the hypothesis statement is extremely clear.