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Erschienen in: Clinical Orthopaedics and Related Research® 9/2008

01.09.2008 | Residents' Corner

Statistics in Brief: The Importance of Sample Size in the Planning and Interpretation of Medical Research

verfasst von: David Jean Biau, MD, Solen Kernéis, MD, Raphaël Porcher, PhD

Erschienen in: Clinical Orthopaedics and Related Research® | Ausgabe 9/2008

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Abstract

The increasing volume of research by the medical community often leads to increasing numbers of contradictory findings and conclusions. Although the differences observed may represent true differences, the results also may differ because of sampling variability as all studies are performed on a limited number of specimens or patients. When planning a study reporting differences among groups of patients or describing some variable in a single group, sample size should be considered because it allows the researcher to control for the risk of reporting a false-negative finding (Type II error) or to estimate the precision his or her experiment will yield. Equally important, readers of medical journals should understand sample size because such understanding is essential to interpret the relevance of a finding with regard to their own patients. At the time of planning, the investigator must establish (1) a justifiable level of statistical significance, (2) the chances of detecting a difference of given magnitude between the groups compared, ie, the power, (3) this targeted difference (ie, effect size), and (4) the variability of the data (for quantitative data). We believe correct planning of experiments is an ethical issue of concern to the entire community.
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Metadaten
Titel
Statistics in Brief: The Importance of Sample Size in the Planning and Interpretation of Medical Research
verfasst von
David Jean Biau, MD
Solen Kernéis, MD
Raphaël Porcher, PhD
Publikationsdatum
01.09.2008
Verlag
Springer-Verlag
Erschienen in
Clinical Orthopaedics and Related Research® / Ausgabe 9/2008
Print ISSN: 0009-921X
Elektronische ISSN: 1528-1132
DOI
https://doi.org/10.1007/s11999-008-0346-9

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