changes its curvature on either side of the mean, and where, from being concave towards the middle line, it spreads out to be convex thereto. When we divide this {79} value by the mean, we get a figure which is independent of any particular units, and which is called the Coefficient of Variability. (It is usually multiplied by 100, to make it of a more convenient amount; and we may then define this coefficient, C, as =ã₤(üã₤ãã₤M)ã₤ûã₤100.)
In regard to the growth of man, Pearson has determined this coefficient of variability as follows: in male new-born infants, the coefficient in regard to weight is 15ôñ66, and in regard to stature, 6ôñ50; in male adults, for weight 10ôñ83, and for stature, 3ôñ66. The amount of variability tends, therefore, to decrease with growth or age.
Similar determinations have been elaborated by Bowditch, by Boas and Wissler, and by other writers for intermediate ages, especially from about five years old to eighteen, so covering a great part of the whole