A Statistical Method for Estimating the Life Expectancy of Certain Shipboard Equipment

Abstract

ABSTRACTThis paper reviews an inexpensive statistical‐sampling methodology that can be used to determine the attrition rates of certain types of shipboard equipment. The methodology relies on surveys that are conducted in conjunction with regularly scheduled ship visits over a period of time and a statistical analysis of the survey results. The statistical technique allows for reasonably accurate estimates to be made of attrition rates.The specific example cited in this paper is related to galley‐type refrigeration equipment, such as salad chillers, beverage dispensers, et cetera. In the case of galley‐type refrigeration equipment, the Navy needs to know whether the Fleet's inventory of equipment relying on Class I Ozone‐Depleting Substances (ODSs) will be replaced through natural attrition by the end of fiscal year (FY) 2005, at which time supplies of ODS‐based refrigerants will no longer be available for use by ship galleys. This paper outlines the process used to gather data, the analysis of the data, and concludes that the Navy's inventory of galley equipment using Class I ODSs will be replaced through natural attrition by the end of FY05.The methodology reviewed by this paper has wider applications. For various types of shipboard equipment, the methodology can also be used to estimate with reasonable accuracy life expectancies, configurations, conditions, and other items of interest.