Brain Weights. In 1905, R. Pearl published the article “Biometrical Studies on Man. I. Variation and Correlation in Brain Weight” (Biometrika, Vol. 4, pp. 13–104) in which he studied the brain weights of Swedish males. The brain weights of a random sample of 225 Swedish men have a mean of 1.40 kg and standard deviation 0.11 kg.

Extending the Concepts and Skills