There are so many articles on internet on Error analysis in measurement but some of them relate least count error with systematic and other with random error and some associate it with both of them. I am so confused that Error in a measurement associated with least count is random or systematic?
Edit :- I think question was not clear about what I want to ask so I am adding an analysis of a measurement. I want to know about error associated with least count of measurement not about Uncertainty due to least count ( ISO guidelines :- Annex F, f.2.2.1 includes it in type B uncertainity) . Let's consider a ideal case in which I have a pen with a known true mass of 12.48gm. When I measure it using a digital weighing machine with a 0.1gm least count, it reads 12.5gm. The uncertainty in measurement due to the least count is ±0.05gm. However, when I compare it to the true value, there's an error of 0.02gm. (In this case we are assuming that there is no calibration or zero error so this error is definitely originated only due to limited resolution of instrument ). Is this error random or systematic?
Reference to 'Least Count Error is Systematic' :-
Reference to 'Least Count Error is Random' :-
Instrument resolution (random) — All instruments have finite precision that limits the ability to resolve small measurement differences. For instance, a meter stick cannot be used to distinguish distances to a precision much better than about half of its smallest scale division (0.5 mm in this case). One of the best ways to obtain more precise measurements is to use a null difference method instead of measuring a quantity directly. Null or balance methods involve using instrumentation to measure the difference between two similar quantities, one of which is known very accurately and is adjustable. The adjustable reference quantity is varied until the difference is reduced to zero. The two quantities are then balanced and the magnitude of the unknown quantity can be found by comparison with a measurement standard. With this method, problems of source instability are eliminated, and the measuring instrument can be very sensitive and does not even need a scale.
Least Count Associated to Both random and systematic:-
3.So upto limited small value least count error behaves as Random error but when least count is of larger value like 1mm or 1cmm then least count error tends to be in one direction only i.e, it behaves as Systematic error.