Unrestricted.2016-11-142011-02-192016-11-141998-05http://hdl.handle.net/2346/22341Age-structured models for biological species have received much study. In this thesis the age-structured population model is extended to a stochastic agestructured model. The model is solved numerically for two age-structured population examples. The calculational results are compared with Monte Carlo calculations. The results indicate that the two calculational methods are in agreement. Persistence times for two age-structured populations are then studied computationally. It is shown that persistence times increase as the number of age groups increases. Also, persistence times are higher for a stohastic age-structured population than for a nonstochastic (or deterministic) age-structured population.application/pdfengStochastic processesAge-structured populationsPopulationStochastic differential equationsThesis