How Different is Different? The Traps and Pitfalls of Applying Statistics on System Performance Evaluation

Statistics is a key component of data analysis for system performance evaluation, but is not always used properly. As engineers, we strive to provide cost-efficient disinfection with known measures of safety. Both design accuracy and design safety factors require a proper understanding of disinfection data and statistical analysis. One important issue is the comparison of system performance of UV disinfection systems at different operating conditions or with previously validated systems. How does one decide whether the system performance is similar? Common errors of applying statistics to system performance evaluation are discussed, and the proper statistical procedure and methods are provided. This study will help environmental engineers and scientists avoid errors for their statistical data analysis during UV system performance evaluation.