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Review
. 2004 Feb;8(1):46-53.
doi: 10.1186/cc2428. Epub 2003 Dec 30.

Statistics review 8: Qualitative data - tests of association

Viv Bewick  1 , Liz Cheek, Jonathan Ball
Affiliations
Review

Statistics review 8: Qualitative data - tests of association

Viv Bewick et al. Crit Care. 2004 Feb.

Abstract

This review introduces methods for investigating relationships between two qualitative (categorical) variables. The chi2 test of association is described, together with the modifications needed for small samples. The test for trend, in which at least one of the variables is ordinal, is also outlined. Risk measurement is discussed. The calculation of confidence intervals for proportions and differences between proportions are described. Situations in which samples are matched are considered.

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References

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    1. Whitley E, Ball J. Statistics review 2: samples and populations. Crit Care. 2002;6:143–148. doi: 10.1186/cc1473. - DOI - PMC - PubMed
    1. Whitley E, Ball J. Statistics review 3: hypothesis testing and P values. Crit Care. 2002;6:222–225. doi: 10.1186/cc1493. - DOI - PMC - PubMed
    1. Bland M. An Introduction to Medical Statistics. 3. Oxford, UK: Oxford University Press; 2001.

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