  The quantum probability distribution arising from single-copy von Neumann
measurements on an arbitrary two-qubit state is decomposed into the local and
nonlocal parts, in the approach of Elitzur, Popescu and Rohrlich [A. Elitzur,
S. Popescu, and D. Rohrlich, Phys. Lett. A 162, 25 (1992)]. A lower bound of
the local weight is proved being connected with the concurrence of the state
$p_L^{\max}= 1-\mathcal{C}(\rho)$. The local probability distributions for two
families of mixed states are constructed independently, which accord with the
lower bound.
