Natural variation within species (following statistical laws) is the basis of selective breeding in agriculture, as well as the theory of eugenics. Photo by Crystal Leigh Shearin.


Applied Eugenics
by Paul Popenoe

“The testing of human customs and institutions in the light of biological principles tallies well with the sociology of our times. This book should command the attention not only of students of sociology, but, as well, of philanthropists, social workers, settlement wardens, doctors, clergymen, educators, editors, publicists, Y.M.C.A. secretaries and industrial engineers.” (complete text online)


Origin of a Normal Probability Curve
From Paul Popenoe, Applied eugenics.