The Interpretation of Averages in Health Professions Research: An Empirical Examination

A potential misinterpretation regarding measures of central tendency was identified in several health sciences textbooks presenting basic statistical procedures. The misinter-pretation involves measures of central tendency derivedfrom skewed unimodal sample distributions. The reviewed textbooks state or imply that in asymmetrical distributions the median is always located between the mode and mean. An example is presented illustrating the fallacy of this assumption. The mean and median will always be to the right of the mode in a positively skewed unimodal distribution and to the left of the mode in a negatively skewed distribution, but the order of the mean and median is impossible to predict or generalize. The assumption that the median always falls between the mode and mean in the calculation of coefficients of skewness has implicationsfor the interpretation of health sciences research.