Which statement describes precision?

Which statement describes precision?

• A. The closeness of repeated measurements to each other.
• B. The closeness of measurements to the true value.
• C. The instrument's calibration.
• D. The uncertainty of measurement.

Answer: (A)

Precision is about reproducibility of measurements. When you measure the same quantity several times, precision means the results are close to one another, forming a tight cluster. This is why the statement describing precision focuses on the closeness of repeated measurements to each other. If the measurements are tightly clustered but centered away from the true value, you have high precision but low accuracy. Accuracy is about closeness to the true value. Calibration of the instrument affects reading correctness and can improve accuracy, and sometimes helps precision by reducing variability, but precision itself is best described by how tightly the results agree with each other. Uncertainty expresses the range within which the true value is expected to lie, reflecting confidence in a measurement, but it is not the definition of precision.

Precision is about reproducibility of measurements. When you measure the same quantity several times, precision means the results are close to one another, forming a tight cluster. This is why the statement describing precision focuses on the closeness of repeated measurements to each other. If the measurements are tightly clustered but centered away from the true value, you have high precision but low accuracy. Accuracy is about closeness to the true value. Calibration of the instrument affects reading correctness and can improve accuracy, and sometimes helps precision by reducing variability, but precision itself is best described by how tightly the results agree with each other. Uncertainty expresses the range within which the true value is expected to lie, reflecting confidence in a measurement, but it is not the definition of precision.