A theory is a well-established principle that has been developed to explain some aspect of the natural world. A theory arises from repeated observation and testing and incorporates facts, laws, predictions, and tested hypotheses that are widely accepted.
A hypothesis is a specific, testable prediction about what you expect to happen in your study. For example, an experiment designed to look at the relationship between study habits and test anxiety might have a hypothesis that states, "We predict that students with better study habits will suffer less test anxiety." Unless your study is exploratory in nature, your hypothesis should always explain what you expect to happen during the course of your experiment or research.
While the terms are sometimes used interchangeably in everyday use, the difference between a theory and a hypothesis is important when studying experimental design. Some important distinctions to note include:
- A theory predicts events in general terms, while a hypothesis makes a specific prediction about a specified set of circumstances.
- A theory has been extensively tested and is generally accepted, while a hypothesis is a speculative guess that has yet to be tested.