%0 Journal Article %T Lower bounds for tails of sums of independent symmetric random variables %A Lutz Mattner %J Mathematics %D 2006 %I arXiv %X The approach of Kleitman (1970) and Kanter (1976) to multivariate concentration function inequalities is generalized in order to obtain for deviation probabilities of sums of independent symmetric random variables a lower bound depending only on deviation probabilities of the terms of the sum. This bound is optimal up to discretization effects, improves on a result of Nagaev (2001), and complements the comparison theorems of Birnbaum (1948) and Pruss (1997). Birnbaum's theorem for unimodal random variables is extended to the lattice case. %U http://arxiv.org/abs/math/0609200v1