Question

Accuracy in measurement relates to:

• A. Systematic error
• B. Random error
• C. Noise
• D. Resolution

Hint:

- Accuracy is limited by Systematic Errors (bias from true value). - Precision is limited by Random Errors (scatter/variance across repeated trials).

Answer 1

The Correct Option is A

Concept: When analyzing measurement systems, it is vital to distinguish between two foundational performance criteria: Accuracy and Precision.
• Accuracy: Indicates how close a measured value is to the true, accepted reference value of the parameter being monitored. Accuracy is directly limited by systematic errors.
• Precision: Indicates how reproducible or consistent repeated measurements are under unchanged operating conditions. Precision is limited by random errors.

Step 1: Defining systematic errors and their impact on accuracy.
Systematic errors (also called bias errors) are consistent, reproducible inaccuracies that shift all measurements in a specific direction away from the true value. Common causes include:
• Poorly calibrated instruments (e.g., a voltmeter reading \(0.1\text{ V}\) too high across its entire scale).
• Zero-offset flaws (e.g., a scale showing a non-zero value when empty).
• Faulty experimental assumptions or environmental bias. Because these factors shift data points consistently away from the true target value, minimizing systematic errors is the primary requirement for improving measurement accuracy.

Step 2: Differentiating from the other choices.

• Random Errors and Noise: These introduce statistical variance and scatter across repeated measurements. They limit the system's precision, but can be minimized by averaging multiple data points. This rules out Options (B) and (C).
• Resolution: This is the smallest change in a physical value that an instrument can detect. While higher resolution allows for finer readings, it does not guarantee accuracy if the instrument remains uncalibrated. This rules out Option (D). Thus, accuracy relates directly to systematic error, verifying Option (A).