On the Gram series on Pearson's system of frequency functions

Abstract

Among the manifold frequency curves that may conceivably arise when it is assumed that, instead of the variate χ itself, a function of the latter, u = ψ(χ), is normally distributed, the logarithmic normal curve occupies a unique position for two reasons: it can be theoretically deduced from a slightly modified elementary error hypothesis and it is applicable in practice to different cases.