2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/140268A bound for functional $Δ(F)=\sup_{x\in\mathbb R}|F(x)-Φ(x)|$ is obtained, which is uniform for all distribution functions $F$ of random variables with zero mean-value and unity variance. Moreover, a two-point distribution is found, for which this bound is reached.4 pages, 3 figuresProbability60E15text