Some Limitations in the Use of Normal Value Tables

Abstract

Analysis of raw data from 822 (224 women and 598 men) Caucasian healthy subjects with age ranging from 19 to 50 years leads to a multiple correlation coefficient equal to 0.75 between vital capacity and age, height and weight. In spite of this highly significant correlation coefficient, the predicting value of the regression equation is very poor: on the one hand, residual fluctuation is very important, on the other hand, because of the small intraindividual variability, ‘normal for the group’ does not necessarily mean ‘normal for the individual’