Inequalities compared

We know that the partial means m_rof a sequence of i.i.d. standardized random variables tend to 0 with probability 1. If we want P{m_k≥εfor some k ≥r}≤δ for given positive ε and δ, how large should we take r? Several (strong) inequalities for the distribution of partial sums providing an answer to this question can be found in the literature (Hájek -Rényi Robbins , Khan ). Furthermore there exist wellknown (weak) inequalities (Bienaymé -Chebyshev , Bernstein , Okamoto ) that give us values of rfor which P{m_r≥ε}≤δ. We compare these inequalities and illustrate them with numerical results for a fixed choice ofε and δ. After a general survey and introduction in section 1, the normal and the binomial distribution are considered in more detail in the sections 2 and 3, while in section 4 it is shown that the strong inequality essentially due to Robbins can give an inferior result for particular distributions.