How do scientists determine if their measurements are accurate?

Accuracy is determined by comparing the measurement against the true or accepted value. Precision can often be adjusted using calibration to yield values that are both accurate and precise. Scientists often report percent error of a measurement, which expresses how far a measured value is from the true value.

Is it possible to determine exact measurements?

Even if there is a finite end to the depths of scale of a certain object, there would be no way to get a simultaneous spot of where every single external boundary-creating particle way on any given object to get an exact measurement.

Can measurements be accurate but not precise?

Accuracy refers to how close a measurement is to the true or accepted value. Precision is independent of accuracy. That means it is possible to be very precise but not very accurate, and it is also possible to be accurate without being precise. The best quality scientific observations are both accurate and precise.

Why is it incorrect to think that the more digits?

Why is it incorrect to think that the more digits you represent in your answer, the more accurate it is? Including more digits in an answer does not necessarily increase its accuracy. Too many digits are meaningless, because they imply a greater accuracy than is possible with the measurements.

What are the merits and drawbacks of using a person’s foot as standard?

(a) A particular person’s foot. Merits: reproducible. Drawbacks: not accessible to the general public; not invariable (could change size with age, time of day, etc.); not indestructible.

Can measurement be accurate but not precise example?

You can also be accurate but imprecise. For example, if on average, your measurements for a given substance are close to the known value, but the measurements are far from each other, then you have accuracy without precision.

Why is it incorrect to think that the more digits the more accurate?

Including more digits in an answer does not necessarily increase its accuracy. The accuracy of an answer is determined by the accuracy of the physical measurement on which the answer is based. Too many digits are meaningless, because they imply a greater accuracy than is possible with the measurements.