This article is part of a series on Medical statistics, edited by Jonathan Ball, Viv Bewick and Liz Cheek.

Review

Statistics review 7: Correlation and regression

Viv Bewick¹ , Liz Cheek¹ and Jonathan Ball²

¹Senior Lecturer, School of Computing, Mathematical and Information Sciences, University of Brighton, Brighton, UK

²Lecturer in Intensive Care Medicine, St George's Hospital Medical School, London, UK

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Critical Care 2003, 7:451-459doi:10.1186/cc2401

Published:	5 November 2003

Abstract

The present review introduces methods of analyzing the relationship between two quantitative variables. The calculation and interpretation of the sample product moment correlation coefficient and the linear regression equation are discussed and illustrated. Common misuses of the techniques are considered. Tests and confidence intervals for the population parameters are described, and failures of the underlying assumptions are highlighted.