Which example best demonstrates both accuracy and precision in measurement?

Which example best demonstrates both accuracy and precision in measurement?

• A. The NIST measures a baseball's mass as 146 grams with consistent results, indicating both accuracy and precision.
• B. A measurement that is exactly equal to the true value but varies significantly on repeated trials.
• C. A measurement that is far from the true value but occurs only once.
• D. A measurement that is slightly close to the true value with large spread.

Answer: (A)

Accuracy means how close a measurement is to the true value, while precision is about how consistent measurements are when you repeat them. The best example of both is a mass around the true value that also produces very similar results across multiple trials. In this case, reporting 146 grams with consistent results shows the measurements are near the real mass and repeatable, so they are both accurate and precise. If a measurement happens to hit the true value on average but varies a lot from trial to trial, that would be accuracy without precision. A single measurement far from the true value shows neither accuracy nor precision. And a measurement close to the true value but with a large spread across trials demonstrates accuracy without precision.

Accuracy means how close a measurement is to the true value, while precision is about how consistent measurements are when you repeat them. The best example of both is a mass around the true value that also produces very similar results across multiple trials. In this case, reporting 146 grams with consistent results shows the measurements are near the real mass and repeatable, so they are both accurate and precise.

If a measurement happens to hit the true value on average but varies a lot from trial to trial, that would be accuracy without precision. A single measurement far from the true value shows neither accuracy nor precision. And a measurement close to the true value but with a large spread across trials demonstrates accuracy without precision.