I am going through the paper, Solving the graph-isomorphism problem with a quantum annealer, by Hen et. al. In the last line of the second paragraph of the second column of page 2, it says,
Since errors of the various measured quantities are inversely proportional to the square root of the number of measurements, this number will be determined from the needed resolution.
I would like to know the reference of the statement that - errors of the various measured quantities are inversely proportional to the square root of the number of measurements.
Thanks.