What best defines an experiment?

• A. A procedure carried out to verify, refute, or establish the validity of a hypothesis
• B. A guess about the outcome of an event
• C. A casual observation without testing a hypothesis
• D. A detailed narrative of a completed study

Answer: (A)

The defining idea is that an experiment is a systematic procedure used to test a hypothesis by collecting data under controlled conditions, with the aim of verifying, refuting, or establishing the hypothesis’s validity. This means designing steps that isolate variables, often including a control, so observations can show whether the hypothesis holds up.

The option that fits this best describes performing a procedure to verify, refute, or establish the validity of a hypothesis. In contrast, a guess about the outcome isn’t testing, casual observations stop short of systematic testing, and a detailed narrative of a completed study is about reporting results rather than the act of testing the hypothesis.