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Sample size and power determination for detecting interactions in mixtures of chemicals

  • Stephanie L. Meadows-Shropshire
  • Chris Gennings
  • W. Hans Carter
Article

Abstract

In the analysis of mixtures of drugs/chemicals it is often of interest to test for the presence of interaction. If the hypothesis of no interaction (additivity) is not rejected, then the analyst may reasonably claim additivity if and only if the study is powered to a desired (e.g., biologically meaningful) level. The objective of this article is to address the sample size and power issues related to testing the hypothesis of additivity at specified mixture points. The study of disinfectant by-products (DBPs) found in drinking water, described in earlier literature, is used to illustrate the procedures for estimating power and sample sizes for detecting interactions at specified mixtures. The four trihalomethanes used in the study are bromodichloromethane (BDCM), chlorodibromomethane (CDBM), chloroform (CHCl3), and bromoform (CHBr3)

Key Words

Additivity Dose-response data Quasi-likelihood Risk assessment 

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Copyright information

© International Biometric Society 2005

Authors and Affiliations

  • Stephanie L. Meadows-Shropshire
    • 1
  • Chris Gennings
    • 2
  • W. Hans Carter
    • 2
  1. 1.Biostatistics and Reporting at Pfizer Inc.New London
  2. 2.Department of BiostatisticsVirginia Commonwealth University, Medical College of VirginiaRichmond

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