Improving Statistical Rigor in Department of Defense Test and Evaluation: Use of Tolerance Intervals in Designed Experiments

Given the push to provide defensible test data in the Department of Defense (DoD) Test and Evaluation (T&E) Enterprise, the use of statistical methods has taken center stage. This research investigates the applicability of statistical tolerance intervals in designed experiments as an analysis method for the DoD T&E technical community. To date, tolerance intervals are scarcely discussed in extant literature as compared to confidence and prediction intervals. The lesser known tolerance intervals can assure a proportion of the population is captured in the design space with some confidence, and have the ability to map out the design space where factors can be reliably tested. Further, this research investigates several two-sided approximate tolerance factors estimated by Monte Carlo simulation and compares them to the exact method. Finally, its applicability to the defense T&E community is presented using a simple case study.