Define precision in this context.

• A. The instrument's calibration status.
• B. The number of significant digits displayed.
• C. The closeness of repeated measurements to each other (repeatability).
• D. The closeness to the true value.

Answer: (C)

Precision is about how consistently you can reproduce a measurement when you repeat the process under the same conditions. It describes how close repeated measurements are to each other (repeatability), not how close they are to the true value. You could obtain very precise results that are consistently off from the true value if the instrument is biased or miscalibrated. That’s why the best answer focuses on the closeness of repeated measurements to one another. The instrument’s calibration status relates to accuracy and traceability, the number of significant digits shows resolution but not repeatability, and closeness to the true value describes accuracy, not precision.