THEORY OF STATISTICS. REFERENCES. The probable errors of various special coefficients, etc., are generally dealt with in the memoirs concerning them, reference to which has been made in the lists of previous chapters: reference has also been made before to most of the memoirs concerning errors of sampling in proportions or percentages. The following is a classification of some of the memoirs in the list below :-— General : 18, 20. Theory of fit of two distributions: 9, 19, 23. Averages and percentiles: 5, 6, 7, 30, 32, 35, 36. Standard deviation: 17, 26. Coefficient of correlation (product-sum and partial correlations): 10, 12, 13, 28, 31, 33, 34. Coefficient of correlation, other methods, normal coefficient, ete. : 24, 29. Cocfficients of association: 34. Coefficient of contingency: 2, 25. As regards the conditions under which it becomes valid to assume that the distribution of errors is normal, ¢f. ref. 14. (1) BLAREMAN, J., “On Tests for Linearity of Regression in Frequency Distributions,” Biometrika, vol. iv., 1905, p. 332. (2) BLAKEMAN, J., and KARL PEARSON, ‘On the Probable Error of the Coefficient of Mean Square Contingency,” Biometrika, vol. v., 1906, pol. (3) BowLEY, A. L., The Measurement of Groups and Sertes ; C. & E. Layton, London, 1903. (4) BowLEYy, A. L., Address to Section I of the British Association, 1906. (5) EpcEworTH, F. Y., “Observations and Statistics: An Essay on the Theory of Errors of Observation and the First Principles of Statistics,” Cambridge Phil. Trans., vol. xiv., 1885, p. 139. (6) EpceworrH, F. Y., ¢ Problems in Probabilities,” Phil. Mag., 5th Series, vol. xxii., 1886, p. 371. (7) EpceEworrtH, F, Y., ‘The Choice of Means,” Phil. Mag., 5th Series, vol. xxiv., 1887, p. 268. (8) EpcewortH, F. Y., “On the Probable Errors of Frequency Constants,” Jour. Roy. Stat. Soc., vol. lxxi., 1908, pp. 381, 499, 651; and Addendum, vol. Ixxii., 1909, p. 81. (9) EupErTON, W. PALIN, ‘Tables for Testing the Goodness of Fit of Theory to Observation,” Biometrika, vol. i., 1902, p. 155. (10) FisHER, R. A., ‘‘The Frequency Distribution of the Values of the Correlation Coefficient in Samples from an Indefinitely large Popula- tion.” Biometrika, vol. x., 1915, p. 507. (11) GresoN, WINIFRED, ‘‘Tables for Facilitating the Computation of Probable Errors,” Biometrika, vol. iv., 1906, p. 385. (12) Heron, D., ““ An Abac to determine the Probable Errors of Correlation Coefficients,” Biometrika, vol. vii., 1910, p. 411. (A diagram giving the probabl« error for any number of observations up to 1000.) (18) Heron, D., “On the Probable Error of a Partial Correlation Coefficient,” Biometrika, vol. vii., 1910, p. 411. (A proof, on ordinary algebraic lines, for the case of three variables, of the result given in (33).) (14) IssErLIs, L., “On the Conditions under which the ‘ Probable Errors’ of » Frequency Distributions have a real Significance,” Proc. Roy. Soc., Series A, vol. xeii., 1915, p. 23. (15) LAPLACE, PIERRE SIMON, Marquis de, Théorie des probabilités, 2¢ édn., 1814. (With four supplements.) (16) PrArL, RayMoND, ‘‘The Calculation of Probable Errors of Certain Constants of the Normal Curve,” Biometrika, vol. v., 1906, p. 190. 254,