In this era of globally competitive world market, many business firms have been using ISO 9000 quality management system, whose principles are leadership, customer focus, people involvement, etc., which are expected and desired to be attained for the various long/short term goals of the business firms. This paper studies whether and how those principles are implemented in the areas of service, manufacturing, etc., and researches the regression relations between business firm's performance and those principles. Using hypothesis testing, we found and showed results which can be referenced for the higher performance of business firms and those can be added to the pool of knowledge about the ISO principles implementation in service and manufacturing industries.