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The Merits of Confidence Intervals Relative to Hypothesis Testing

Published online by Cambridge University Press:  21 June 2016

David Bimbaum
Affiliation:
Applied Epidemiology, Sidney, British Columbia
Samuel B. Sheps*
Affiliation:
University of British Columbia, Vancouver, British Columbia
*
Department of Health Care and Epidemiology, 5804 Fairview Ave., Vancouver, BC, V6T 1Z3

Extract

A variety of statistical tests of a null hypothesis commonly are used in biomedical studies. While these tests are the mainstay for justifying inferences drawn from data, they have important limitations. This report discusses the relative merits of two different approaches to data analysis and display, and recommends the use of confidence intervals rather than classic hypothesis testing.

Formulae for a confidence interval surrounding the point estimate of an average value take the form: d= ±zσ/√n, where “d” represents the average difference between central and extreme values, “z” is derived from the density function of a known distribution, and “a/-∨n” represents the magnitude of sampling variability. Transposition of terms yields the familiar formula for hypothesis testing of normally distributed data (without applying the finite population correction factor): z = d/(σ/√n).

Type
Statistics for Hospital Epidemiology
Copyright
Copyright © The Society for Healthcare Epidemiology of America 1992

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