What is precision and accuracy in physics? how it is calculated?

Question

What is precision and accuracy in physics? how it is calculated?

Answer 1

lets say we shot a missile at a house

its 1000 miles away

the house is 50 x 50 sq foot target

we aim at door k**b

we hit the door

crater is 100 feet across

reduce it all to fractions and there you go

its just a % of what you want and what you get

Answer 2

Precision is how close a group of results are to each other. Say you measured the speed of a particle ten times and the result was the same every time, that would be a precise result. It can be represented in a number of ways but giving the standard deviation of the results is common.

Accuracy is how close the results are to the true value. So if the average of the ten results was exactly the true speed of the particle then the result would be accurate.

The two are not necessarily related. Say the stopwatch we used in measureing the speed of the particle was broken and always gave the same reading. The results would be very precise (because they would all be the same) but would not be accurate (because they are not near the true speed. Alternatively suppose we were not very good with the stopwatch. Then the results would not be precise (because we would get large differences in the results) but they could still be accurate (because the average is very close to the true speed).