Systematic Error Explains Consistent Discrepancy

Steps:

• The liquid is well-mixed, ensuring uniform temperature throughout.
• All 10 students agree on both readings, indicating consistent observations without variation.
• The thermometers show a fixed 2°C difference, suggesting a bias in one or both devices.
• This points to a non-random, reproducible error source.

Why D is correct:

• Systematic error is a consistent bias in measurement (e.g., calibration offset), causing all readings from one thermometer to deviate predictably, as defined in measurement theory.

Why the others are wrong:

• A: Well-mixed liquid implies uniform temperature, ruling out spatial variations.
• B: Precision concerns repeatability; agreed readings show high precision, just inaccuracy.
• C: Random error causes variable results; consistent agreement eliminates randomness.

Final answer: D