Random error is defined as:

• A. Result of low precision and uncertainty in measurements
• B. Consistent bias in the measurement system
• C. Random fluctuations in measurements
• D. A fixed offset across all measurements

Answer: (C)

Random error is the unpredictable, non-directional variation that occurs when measuring. When you repeat measurements under similar conditions, the results scatter around the true value due to uncontrollable factors like detector noise, environmental changes, or sample inhomogeneity. This kind of variability affects precision—the consistency of repeated measurements—without producing a fixed offset. In contrast, systematic bias or a fixed offset would shift all measurements by about the same amount in the same direction, which is not what random error describes. So the best description is the idea that measurements fluctuate randomly from one trial to the next.