Essays in eugenics / by Sir Francis Galton.

  • Galton, Francis, 1822-1911.
Date:
1909
Catalogue details

Licence: In copyright

Credit: Essays in eugenics / by Sir Francis Galton. Source: Wellcome Collection.

    17/128 (page 5)
    will, therefore, venture to adapt the phraseology of the allegory to my present purpose by substituting for “ talent ” the words “ normal- talent.” The value of this normal talent in respect to each and any specified quality or faculty is such that one-quarter of the people receive for their respective shares more than one normal-talent over and above the average of all the shares. Our normal-talent is there- fore identical with what is technically known as the ‘‘probable error.” Therefrom the whole of the following table starts into life, evolved from that of the ^^probability integral^ Table I.—Normal distribution (to the nearest per ten-thousand and to the nearest per hundred.) M -4° -3° -2° -1° I + 1 M I 0 + 2° + 3° +4° 1 V and below u t 8 V R S T U V and above. Total 35 180 672 1613 2500 2500 1613 672 180 35 10,000 2 7 16 25 25 16 7 2 100 It expresses the distribution of any normal quality, or any group of normal qualities, among 10,000 persons in terms of the normal-talent. The M in the upper line occupies the position of Mediocrity, or that of the average of what all have received : the + T, +2°, etc., and the -1°, -2°, etc., refer to normal talents. These numerals stand as