A hypothesis in an experiment is:

• A. A testable prediction about a relationship between variables.
• B. A guess without evidence.
• C. A summary of results.
• D. An observation of a single event.

Answer: (A)

A hypothesis is a statement that makes a testable prediction about how changing one variable will affect another. It describes a relationship between variables and is crafted so you can collect data to support or refute it. It isn’t just a guess; it’s based on prior evidence or reasoning and is defined in a way that can be tested through observation or experimentation. It’s not a summary of results—that comes after the experiment. It’s also not merely an observation of a single event, which is just a factual data point you might record. Often you’ll see it framed as an if-then statement that links the independent variable (what you change) to the dependent variable (what you measure), making the predicted relationship clear and testable.