2 THEORY OF STATISTICS. 
effect of removing conditions of Small chances, law of, 265-266, 366 
simple sampling on standard error 370; refs., 273, 393. 
of mean, 347-350 ; standard error. Snow, E. C., refs., estimates of popu- 
of standard-deviation and co- lation, 130, 253 ; lines and planes 
efficient of variation, 351 ; of co- of closest fit, 209. 
efficients of correlation and re- Soil surveys, errors in, refs., 396. 
gression, 352 ; of correlation-ratio Soper, H. E., frequency arrays, ref., 
and test for linearity of regression, 393: 
352 ; refs., 354-356, 395. — refs., probable error of correlation- 
Saunders, Miss E. R., data cited coefficient, 355, 395; of biserial 
from, 37. expression for correlation - co- 
Scale-reading, bias in, 362-363. efficient, 355; tables of exponen- 
Scheibner, W., difference between tial binomial limit, 273. 
arithmetic and geometric, arith- Southey, Robert, cited re Cosin’s 
metic and harmonic means, (qu. 8 Names of the Roman Catholics, 
and qu. 9) 156. etc., 100. 
Scripture, E. W., use of word Spearman, C., effect of errors of 
“statistics,” 3. observation on the standard-de- 
Secrist, H., refs., Introduction to viation and coefficient of correla- 
Statistical Methods, 398. tion, 213-214. Refs., effect of 
Semi-interquartile range. See Quar- errors of observation, 225, 333, 
tiles. 391 ; rank method of correlation, 
Sex-ratio of births : correlation with 335 
total births, 163, 175, 207; dia-  Splawa-Neyman, J., refs., probable 
gram, 176; constants, (qu. 3) 189; errors, 395. 
application of the theory of sam- Spurious correlation of indices, 215- 
pling to, 262-264, (qu. 7) 275, (qu. 216 ; refs., 226, 392. 
1, 2) 289, refs., 273; standard Standard-deviation. See Deviation, 
error of ratio of male to female standard. 
births, (qu. 11) 275. Standardisation of death-rates, 223 
Shakespeare, W., use of word 225 ; refs., 226, 392. 
statist,” 1. Statist, occurrence of the word in 
Sheppard, W. F., correction of the Shakespeare and in Milton, 1. 
standard-deviation for grouping, Statistical, introduction and de- 
212, 307 ; theorem on correlation velopment. .in the meaning of the 
of a normal distribution grouped word, 1-5 ; S. Account of Scotland, 
round medians, (qu. 4) 334; 2; Royal S. Society, 3 ; methods, 
normal curve tables, 337; stan- purport of, 3-5; def., 5. 
dard errors of percentiles, 344. Statistics, introduction and develop- 
Refs., calculation and correction ment in meaning of word, 1-5; 
of moments, 225; normal curve def., 5; theory of, def., 5. 
and correlation, theory of sam-  Statures of males in U.K., tables, 88, 
pling, 314, 333, 355; tables of 90; diagrams, 89, 91; calcula- 
normal function and its integral, tion of mean, 112; means and 
359. medians, 117, (qu. 1) 131; stan- 
Significant differences, 266. dard-deviation, 141 ; percentiles, 
Sinclair, Sir John, use of words 153 ; standard-deviation, “mean 
“ statistics,” ¢ statistical,” 2. deviation, and quartiles, (qu. 1) 
Skew or asymmetrical frequency- 155 ; distribution fitted to normal 
distributions, 90-102. See also curve, 305-306, 307-308; dia- 
Frequency-distributions. gram, 306; standard errors of 
Skewness of frequency-distributions, mean and median, of first to 
107 ; measures of, 149-150. ninth deciles, 341, 343, 344-345 ; 
Slutsky, E., refs., fit of regression of standard-deviation and semi- 
lines, 209, 391. interquartile range, (qu. 5) 355. 
420