2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/123014We consider the general measurement scenario in which the ensemble average of an operator is determined via suitable data-processing of the outcomes of a quantum measurement described by a POVM. After reviewing the optimization of data processing that minimizes the statistical error of the estimation, we provide a compact formula for the evaluation of the estimation error.4 pages, contribution for the proceedings of the QCMC06 at Tsukuba, Japan. qcmc06.styQuantum Physicstext