Discuss the difference between accuracy and precision Which

Discuss the difference between accuracy and precision. Which can be improved through calibration? Which can be improved by collecting multiple points and averaging?

Solution

Accuracy: Accuracy refers to how closely the measured value of a quantity corresponds to its \"true\" value or know value or standard value. For example, you measured the acceleration due to Earth\'s gravity at sea level. The value of g should ideally be approximately 9.806 m/s². If you measured a value of g = 9.82 m/s², that is accurate compared to if you measure g = 9.5 m/s².

Precision: Precision expresses the degree of reproducibility or agreement between repeated measurements. In other words how close you outputs are repeated each time you measure. For example, for the same problem mentioned above, if you measure five time and get 9.10, 9.11, 9.12, 9.13, 9.14 m/s² (average g = 9.12, the measurement is precise but not accurate. But if you measure, 9.6, 9.7, 9.8, 9.9,10 m/s² (average g = 9.8), then your measurement is accurate but not precise.

As explained above, precision can be improved through calibration for example if you calibrate your measurement device in such a way that it is offset by 0.7, the your measurement will be 9.8, 9.81, 9.82, 9.83, 9.84, so that average is now close to 9.82 m/s².

Similarly collecting multiple data and do averaging helps in better accuracy.