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On Bounds for Probability Generating Functions
Author(s) -
Narayan P.
Publication year - 1981
Publication title -
australian journal of statistics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.434
H-Index - 41
eISSN - 1467-842X
pISSN - 0004-9581
DOI - 10.1111/j.1467-842x.1981.tb00764.x
Subject(s) - upper and lower bounds , combinatorics , mathematics , random variable , probability generating function , branching process , moment (physics) , function (biology) , variable (mathematics) , branching (polymer chemistry) , moment generating function , discrete mathematics , statistics , mathematical analysis , physics , quantum mechanics , composite material , materials science , evolutionary biology , biology
Summary Brook (1966) gave an upper bound for the moment generating function (m.g.f.) of a positive random variable (r.v.) in terms of its moments, and used this to obtain an upper bound for the probability generating function (p.g.f.) and hence the extinction probability of a simple branching process. Agresti (1974) rederived this bound of the p.g.f. and used it to obtain a lower bound of the expectation of extinction time of a branching process. In both of these applications the random variable is integer valued, and for this class we improve on Brook's bound by deriving the best upper bound of the p.g.f. Our method, which is a variant of Brook's (1966) is used later to obtain the lower bound of the p.g.f. when the third moment is also known.