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Two‐sample scale tests for comparison of metabolic rates for styrene in previously exposed and unexposed groups
Author(s) -
Chen ChuChih,
Wu KuenYuh,
Balakrishnan N.
Publication year - 2004
Publication title -
statistics in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.996
H-Index - 183
eISSN - 1097-0258
pISSN - 0277-6715
DOI - 10.1002/sim.1617
Subject(s) - statistics , styrene , sample size determination , estimator , inference , statistical inference , scale (ratio) , sample (material) , mathematics , econometrics , chemistry , chromatography , computer science , organic chemistry , physics , quantum mechanics , artificial intelligence , copolymer , polymer
Statistical analysis procedure in two‐sample treatment difference, as well as alternative hypothesis, may play a central role in statistical inference, especially in small sample size case. In this paper, simple non‐parametric two‐sample permutation tests for scale difference based on the Hodges–Lehmann estimator are reformulated, and are applied to a study examining whether previous styrene exposure increases (thus a one‐sided alternative hypothesis rather than a two‐sided one) the human liver's metabolic ability to convert styrene into styrene oxide, in which a three‐compartment physiologically based pharmacokinetic (PBPK) model was used to compare the estimated metabolic constant κamong the previously exposed and unexposed groups. Contrary to the previous conclusion, the proposed tests for scale difference identified from a mixed‐effects model showed a significant result. Copyright © 2004 John Wiley & Sons, Ltd.