What is Accuracy?
The accuracy is most common term which is used in process of all sorts of measurements including engineering experiments, scientific calculations and industrial experiences as well. Accuracy is indicator of both systematic and random errors which shows how different the true value is from its reference value. Lesser difference in both said values means high accuracy and bigger difference indicate lower accuracy. Measurement results normally based on accuracy and accurate results made the measurement perfect.
Definition:
As explained above so we can say the term accuracy refers to “closeness of measured value to its reference value” or
Accuracy is characteristic of measuring system which shows difference between measured quantity and its absolute standard or value.
True value
Refers to value of physical quantity that is measured locally by a measuring instrument or shown by a gauge in such conditions where probability of errors is almost zero..This value can use as a reference standard value in measurement systems and analytical system s.
The Difference between precision and accuracy:
The difference between both accuracy and precision is shown in Table:
| Precision | Accuracy |
| Degree of closeness of measured values to each other. | Degree of closeness of measured value to its reference value. |
| Describes measured values exactness. | Describes systemic and random errors. |
| Shows variation in measurements when you measure same object or part. | Shows difference between measured value and true value. |
| Indicates measuring instruments reliability also. | Indicates how correct measuring process is. |
In above figure the difference between precision and accuracy is graphical form .The yellow portion of graph shows values nearer to each other which means it’s precision and in orange portion values are closer to reference value so it shows accuracy.
Is the precise measurement is accurate too?
The accurate value con be precise value and vice versa also but it is not necessary for both should be there in same value the picture shows how they can be differ from each other for a same aimed measuring point. Six small circles indicates measured values and aim or reference point is center of big circles.
