{ "id": "1008.0116", "version": "v2", "published": "2010-07-31T18:02:20.000Z", "updated": "2011-06-27T09:50:29.000Z", "title": "On the relation between the distributions of stopping time and stopped sum with applications", "authors": [ "M. V. Boutsikas", "A. C. Rakitzis", "D. L. Antzoulakos" ], "comment": "18 pages, 4 figures", "categories": [ "math.ST", "stat.TH" ], "abstract": "Let $T\\$ be a stopping time associated with a sequence of independent random variables $Z_{1},Z_{2},...$ . By applying a suitable change in the probability measure we present relations between the moment or probability generating functions of the stopping time $T$ and the stopped sum $%S_{T}=Z_{1}+Z_{2}+...+Z_{T}$. These relations imply that, when the distribution of $S_{T}$\\ is known, then the distribution of $T$\\ is also known and vice versa. Applications are offered in order to illustrate the applicability of the main results, which also have independent interest. In the first one we consider a random walk with exponentially distributed up and down steps and derive the distribution of its first exit time from an interval $(-a,b).$ In the second application we consider a series of samples from a manufacturing process and we let $Z_{i},i\\geq 1$, denoting the number of non-conforming products in the $i$-th sample. We derive the joint distribution of the random vector $(T,S_{T})$, where $T$ is the waiting time until the sampling level of the inspection changes based on a $k$-run switching rule. Finally, we demonstrate how the joint distribution of $%(T,S_{T})$ can be used for the estimation of the probability $p$ of an item being defective, by employing an EM algorithm.", "revisions": [ { "version": "v2", "updated": "2011-06-27T09:50:29.000Z" } ], "analyses": { "subjects": [ "60G40", "60G50", "62E15" ], "keywords": [ "stopping time", "stopped sum", "application", "joint distribution", "independent random variables" ], "note": { "typesetting": "TeX", "pages": 18, "language": "en", "license": "arXiv", "status": "editable", "adsabs": "2010arXiv1008.0116B" } } }