Key Concepts: Accuracy vs Precision

Core Definitions

• Accuracy: How close a measurement is to the true or accepted value.
• Precision: How close repeated measurements are to each other (reproducibility).
• Percent Error: Measures accuracy: |experimental − accepted| / accepted × 100%.
• High Accuracy, High Precision: Measurements are close to the true value AND close to each other.
• High Precision, Low Accuracy: Measurements are close to each other but far from the true value.
• Systematic Error: A consistent error that affects accuracy (e.g., a miscalibrated instrument).