A valid conclusion is supported by valid data, obtained from an appropriate experimental design and sound reasoning.

• A. A conclusion that agrees with the hypothesis regardless of data.
• B. A conclusion drawn from anecdotal evidence.
• C. A conclusion supported by data from a properly designed experiment.
• D. A conclusion that uses the most precise instrument.

Answer: (C)

In science, a valid conclusion comes from data gathered in a properly designed experiment and from reasoning that connects the results to the claim being made. The best conclusion is one that is supported by data obtained under controlled conditions, with appropriate controls and replication, and explained with logical interpretation of what the results mean. If a conclusion simply agrees with the hypothesis regardless of what the data show, it ignores what was observed. Relying on anecdotes provides evidence that isn’t representative or reliable. Having a very precise instrument helps reduce measurement error, but precision alone doesn’t guarantee that the design is valid or that the results are meaningful. So the supported, well-designed-data path is the strong choice.