A good hypothesis is a statement that helps to explain the occurrence of a specified group of observable phenomena. A scientist begins with a question she wishes to answer. The scientist turns that question into a statement. It is important that this statement reflects an understanding of scientific principles and showcases preliminary research.
A hypothesis is not simply a wild guess. The experiment sets out to prove or disprove the hypothesis. The individual conducting the experiment must write the hypothesis in simple, concise language. This guarantees the hypothesis is testable. “How many times a week should a man exercise?” is an example of a bad hypothesis because it is a question, and it is not testable. A good hypothesis on the same topic could be worded in this manner: “If a male exercises more than twice a week, he is less susceptible to heart disease.” Observable factors that can be measured are an essential characteristic of a good hypothesis. A good hypothesis addresses a general phenomenon and not an isolated occurrence. Scientists must consider the variables that are going to be manipulated in the experiment and be sure to include them in the hypothesis itself. Examples of variables include participants, what changes during the testing and what the changes will be. Finally, a good hypothesis is based on logic.