Kathman, Steven Jay Jr.2014-03-142014-03-141999-12-07etd-121499-161722http://hdl.handle.net/10919/30101Random variables defined on the natural numbers may often be approximated by Poisson variables. Just as normal approximations may be improved by saddlepoint methods, Poisson approximations may be substantially improved by tilting, expansion, and other related methods. This work will develop and examine the use of these methods, as well as present examples where such methods may be needed.In CopyrightTiltingPoisson approximationGenerating functionDissertationhttp://scholar.lib.vt.edu/theses/available/etd-121499-161722/