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A study on the Poisson, geometric and Pascal distributions motivated by Chvátal’s conjecture. (English) Zbl 1515.60044

Summary: Let \(B (n, p)\) denote a binomial random variable with parameters \(n\) and \(p\). Vašek Chvátal conjectured that for any fixed \(n \geq 2\), as \(m\) ranges over \(\{0, \dots, n\}\), the probability \(q_m := P(B(n, m/n) \leq m)\) is the smallest when \(m\) is closest to \(\frac{2n}{3}\). This conjecture has been solved recently. Motivated by this conjecture, in this paper, we consider the corresponding minimum value problem on the probability that a random variable is not more than its expectation, when its distribution is the Poisson distribution, the geometric distribution or the Pascal distribution.

MSC:

60C05 Combinatorial probability
60E15 Inequalities; stochastic orderings

References:

[1] Barabesi, L.; Pratelli, L.; Rigo, P., On the Chvátal-Janson conjecture, Statis. Probab. Lett., 194, Article 109744 pp. (2023) · Zbl 1506.60021
[2] Doerr, B., An elementary analysis of the probability that a binomial random variable exceeds its expectation, Statis. Probab. Lett., 139, 67-74 (2018) · Zbl 1392.60022
[3] Greenberg, S.; Mohri, M., Tight lower bound on the probability of a binomial exceeding its expectation, Statis. Probab. Lett., 86, 91-98 (2014) · Zbl 1293.60024
[4] Janson, J., On the probability that a binomial variable is at most its expectation, Statis. Probab. Lett., 171, Article 109020 pp. (2021) · Zbl 1457.60015
[5] Pelekis, C.; Ramon, J., A lower bound on the probability that a binomial random variable is exceeding its mean, Statis. Probab. Lett., 119, 305-309 (2016) · Zbl 1397.60055
[6] Sun, P., Strictly unimodality of the probability that the binomial distribution is more than its expectation, Discrete Appl. Math., 301, 1-5 (2021) · Zbl 1478.60036
[7] Sun, P.; Hu, Z.-C.; Sun, W., The extreme values of two probability functions for the Gamma distribution (2023), arXiv:2303.17487v1
[8] Xu, K.; Li, F.-B; Hu, Z.-C., Study on Poisson distribution and geometric distribution motivated by Chvátal’s conjecture (2022), arXiv:2210.16515v1
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