title: On using a normal approximation for the noncentral t-distribution in determining upper limits for future sample relative repeatability and reproducibility standard deviations.
abstract: Formulas, based on a normal approximation for the noncentral t-distribution, were developed to compute 100p% one-tailed upper limits for future sample relative repeatability and relative reproducibility standard deviations (RSDr,% and RSDR,%) collaboratively obtained under a completely randomized model. The accuracy of the formulas for obtaining a one-tailed upper limit for the future sample RSDr,% was assessed by comparing the computed noncentral t-distribution-based upper limits with the one-tailed upper limits based on a normal approximation for the noncentral t-distribution. The accuracy of the normal approximation formula for obtaining a one-tailed upper limit for a future sample RSDR,% was assessed by comparing the formula-based one-tailed upper limits with those obtained in a Monte Carlo simulation study.
authors.affiliation: U.S. Food and Drug Administration, Center for Food Safety and Applied Nutrition, DHHS, Office of Food Defense, Communication and Emergency Response, Division of Public Health and Biostatistics, College Park, MD 20740-3835, USA. fdmc5100@yahoo.com
authors.forename: Foster D
authors.initials: FD
authors.lastname: McClure
authors.forename: Jung K
authors.initials: JK
authors.lastname: Lee
mesh_terms: D000704:Analysis of Variance; D003201:Computers; D007753:Laboratories / Q000592:standards; D009010:Monte Carlo Method; D016011:Normal Distribution; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity