1F4 THEORY OF STATISTICS.
REFERENCES.
General.
(1) FECHNER, G. T., ‘ Ueber den Ausgangswerth der kleinsten Abweichungs-
summe, dessen Bestimmung, Verwendung und Verallgemeinerung,”
Abh. d. kgl. sichs. Ges. d. Wissenschaften, vol. xviii. (also numbered
vol. xi. of the 4bk. d. math.-phys. Classe) ; Leipzig, 1878, p. 1.
Standard Deviation.
(2) PEARSON, KARL, ‘Contributions to the Mathematical Theory of Evolution
(i. On the Dissection of Asymmetrical Frequency-curves),” Phil. Trans.
Roy. Soc., Series A, vol. clxxxv., 1894, p. 71. (Introduction of the
term ¢¢ standard deviation,” p. 80.)
Mean Deviation.
(8) LAPLACE, PIERRE SimoN, Marquis de, Théorie analytique des probabili-
tds: 2m supplément, 1818. (Proof that the mean deviation is a
minimum when taken about the median.)
(4) TRACHTENBERG, M. I., ‘“ A Note on a Property of the Median,” Jour.
Roy. Stat. Soc., vol. 1xxviii., 1915, p. 454. (A very simple proof of
the same property.)
Method of Percentiles, including Quartiles, etc.
(5) GALTON, FRANCIS, “‘ Statistics by Intercomparison, with Remarks on the
Law of Frequency of Error,” Phil. Mag., vol. xlix. (4th Series), 1875,
pp. 83-46.
(6) GALTON, FRANCIS, Natural Inheritance ; Macmillan, 1889. (The method
of percentiles is used throughout, with the quartile deviation as the
measure of dispersion.)
Relative Dispersion.
(7) PEARSON, Karr, “ Regression, Heredity, and Panmixia,” Phil. Trans.
Roy. Soc., Series A, vol. clxxxvii., 1896, p. 253. (Introduction of
¢¢ coefficient of variation,” pp. 276-7.)
(8) VERSCHAEFFELT, E., “Ueber graduelle Variabilitit von pflanzlichen
Eigenschaften,” Ber, deutsch. bot. Ges., Bd. xii., 1894, pp. 350-55.
Skewness.
(9) Pearson, KARL, ‘‘ Skew Variation in Homogeneous Material,” Phil.
Trans. Roy. Soc., Series A, vol. elxxxvi., 1895, p. 343. (Introduction
of term, p. 370.)
Calculation of Mean, Standard-deviation, or of the General
: Moments of a Grouped Distribution.
We have given a direct method that seems the simplest and best for
the elementary student. A process of successive summation that has
some advantages can, however, be used instead. The student will
find a convenient description with illustrations in—
(10) ELpERTON, W. PALIN, Frequency-curves and Correlation ; C. & E.
Layton, London, 1906.
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