ABSTRACT
This chapter provides an in-depth analysis of Francis Galton’s December 1888 paper in which he revealed his discovery of mathematical correlation. The major points and discussions in this chapter are:
· Galton’s December 1888 paper was the birth of mathematical statistics, at least according to his biographers.
· There are large number of erroneous ways that his December 1888 paper has been referenced by historians, statisticians, and by Galton himself.
· His own writings demonstrate that he discovered the correlation coefficient gradually while working on other projects, rather than suddenly while taking a solitary walk in the countryside (as has been often claimed).
· There are an embarrassingly large number of errors in his paper.
· He purposefully chose “Co-relation” as the first word in his paper’s title, rather than “Correlation”, because co-relation was the best word for the concept he was introducing; the motivation for this choice was likely provided by his close friend William Grove.
· Galton made multiple false claims in his paper’s first sentence as well as elsewhere on his first page and in his analytical conclusions in later pages.
· A reasoned and historical explanation is provided for what Galton meant when he said that the regression coefficients of 0.26 and 2.5 are not “reciprocal”.
· A corrected version of the paper’s only “figure” is provided, and the errors in his original version are discussed.
· Analyses of Galton’s December 1888 paper by other historians are discussed.
