Moment conversion method for reliability evaluation of very expensive system

For the reliability problem of systems that are too expensive to be tested more than once or twice, it needs to evaluate the reliability through evaluating its subsystems and the components of the subsystems. It was found that moment conversion method is an effective tool for this purpose. using this method, three key equations were derived, they were used to convert test data of components and subsystems into equivalent test data for the total system and to compute the reliability of the total system for any given confidence level.