2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/149465Let $X=\sum ε_n x_n$ be a Rademacher series with vector-valued coefficients. We obtain an approximate formula for the distribution of the random variable $||X||$ in terms of its mean and a certain quantity derived from the K-functional of interpolation theory. Several applications of the formula are given.Functional Analysis46B09, 60G50text