What is a hypothesis?

• A. A random guess about outcomes.
• B. A rule for data collection.
• C. A summary of research results.
• D. A testable prediction about the relationship between variables, often derived from a theory.

Answer: (D)

A hypothesis is a testable prediction about how variables relate to each other, usually grounded in theory. It specifies what you expect to observe under certain conditions and can be tested with data to determine if the prediction holds. It isn’t a random guess, a rule for data collection, or a summary of results. For example, a psychologist might hypothesize that longer sleep improves memory performance, so people who get eight hours of sleep should perform better on a memory task than those who get only four hours. This kind of statement is testable and falsifiable, which is what makes it a hypothesis.