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A note on sample size computation for testing interactions
Author(s) -
Lachenbruch Peter A.
Publication year - 1988
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.4780070403
Subject(s) - computation , sample size determination , computer science , sample (material) , statistics , econometrics , mathematics , algorithm , physics , thermodynamics
This paper discusses a simple method to compute sample sizes for testing interactions in analysis of variance. It uses orthogonal contrasts to determine the power. For the 2 × 2 table this gives a single degree of freedom contrast for consideration. For larger designs, one must consider a set of contrasts. The use of Bonferroni or Scheffé critical values is discussed. This method allows the user to compute easily a sample size without recourse to the non‐central F distribution.