  Real numbers from the interval [0, 1] are randomly selected with uniform
distribution. There are $n$ of them and they are revealed one by one. However,
we do not know their values but only their relative ranks. We want to stop on
recently revealed number maximizing the probability that that number is closest
to $\frac{1}{2}$. We design an optimal stopping algorithm achieving our goal
and prove that its probability of success is asymptotically equivalent to
$\frac{1}{\sqrt{n}}\sqrt{\frac{2}{\pi}}$.
