Unbiased Variance Estimators in System Reliability of Mixed Configuration Models

Unbiasedness is a highly desirable property of an Estimator if testing samples are small. We discuss the role of Unbiased Variance Estimator in System Reliability that can be applicable for any system decomposed into series-parallel connections as long as components Reliability Estimates are mutually independent. We present two different models in this paper and comparative study has been made based on the biased and unbiased nature of the system and components. Certain Illustrations related to these models are provided with Fault-Tree Analysis Approach.