Overview
This lecture explains the difference between accuracy and precision in measurements, using examples to clarify how they relate to true values and consistency.
Accuracy
- Accuracy measures how close a value is to the true or target value.
- For example, if a 20 kg dumbbell is weighed and results are close to 20 kg, the scale is accurate.
- Being accurate is like consistently hitting near the center of a target.
Precision
- Precision refers to how consistent or repeatable measurements are, regardless of their closeness to the true value.
- If repeated measurements yield similar results, the process or instrument is precise.
- For instance, weighing a 20 kg dumbbell three times and getting similar but wrong results shows precision without accuracy.
Comparing Accuracy and Precision
- Accurate and precise: measurements are both near the true value and closely grouped.
- Accurate but not precise: measurements average out to the true value but are scattered.
- Precise but not accurate: measurements are closely grouped but far from the true value.
- Neither precise nor accurate: measurements are random and not near the true value.
Importance of Accuracy and Precision
- Both accuracy and precision are necessary for reliable measurements in fields like research, construction, and engineering.
- Inaccurate or imprecise measurements can lead to misleading or even dangerous outcomes.
Key Terms & Definitions
- Accuracy — how close a measured value is to the actual or true value.
- Precision — how consistent repeated measurements are, regardless of their closeness to the true value.
Action Items / Next Steps
- Review examples of accuracy and precision to ensure understanding.
- Practice identifying whether a scenario demonstrates accuracy, precision, both, or neither.