What is difference between Precision and Accuracy ?

For any ordinary man , both the terms are equivalent but for those have an analytical brain, both the terms are very different.
Accuracy is actually closeness of agreement between observed value and known reference standard. In mathematical or statistical terms , it is also known as the central tendency which can be calculated as mean, mode and median.

But precision is the measure of dispersion between several individual observations of relevant quality characteristics. Precision describes consistency of the process and it is calculated by range and Standard deviation.

Little bit confuse? Let me explain......

Suppose you are an archer or a shooter and you have to hit a target or a circle. If your bullets or arrow are not hitting the exact target but all the bullets or arrows are just hitting outside the target but all are in a same portion , it means you are précised on the target but if your bullets or arrows are near by target but all are scattered into different direction of the target , it is accuracy. if you hit the target, It is accurate and précised.

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