I¥ IX, 47
310: advantages of q.d. as a Russell, E. J., refs., errors of agrimeasure
 of dispersion, 148-149; cultural experiment, 396.
difference between deviations of Rutherford, E., ref., law of small
quartiles from median as measure chances, 273.
of skewness, 149-150; ratio of
q.d. to median as measure of re- SAMPLING, theory of, generally, 254
lative dispersion, 149; q.d. of 355 ; the problem, 254-256 ; refs.,
normal curve, 310; standard 273, 289, 313-315, 354-355, 392,
errors, 337-341, 341-343. 393, 395.
Quetelet, L. A. J., refs., Lettres surla ~~ — of attributes: conditions asthéorie
 des probabilités, 272, 361. sumed in simple sampling, 255-256,
 259-262 ; random in sense of
simple sampling, 289 ; standard-Raxpom
 sampling, in sense of simple deviation of number or proportion
sampling, 289. of successes in n events, 256-257,
Range, unsuitability of, as a measure 299-300 ; examples from artificial
of dispersion, 133. chance, 258-259; application to
Ranks, 143, 153 ; methods of corre- sex-ratio, 262-264; when numlation
 based on (refs.), 333. bers in samples vary, 264-265 ;
Ranunculus, frequency of petals, when chance of success or failure
102 ; unsuitability of median for is small, 265-266, 366-370 ; stansuch
 distributions, 117. dard error, def., 267 ; comparing
Registrar-General : correction or a sample with theory, 267-268 ;
standardisation of death-rates, comparing one sample with an-224,
 refs, 226, 392; estimates other independent therefrom, 268-of
 population, refs., 130; data 271 ; comparing one sample with
cited from Reports, 32-33, 52-53, another combined with it, 271-77,
 98, 163, 197-199, 199-201, 272 ; limitations to interpretation
222, 263, 283, 284, 285-286. of standard error when = is small,
Regressions, generally, 175-177; inverse interpretation, 276-279 ;
def., 175; total and partial, 233; limits as a measure of untruststandard
 errors of, 352; non- worthiness, 279-281; effect of
linear, 201-202, 205-206, 352; removing conditions of simple
direct deduction, 365-366; refs., sampling, 281-289; sampling
208-209, 391. from limited material, 287; bi-Relative
 dispersion, 149. nomial distribution, 291-300 ; nor-Reserves
 and discounts in American mal curve, 300-313 ; normal corbanks,
 correlation, 162 ; diagram, relation, 317-334; law of small
facing 166. chances, 366-370 ; refs., 272-273,
Rhind, A., ref., tables for computing 392, 393. See also Binomial
probable errors, 355, 359. series ; Hypergeometrical series ;
Rhodes, E. C., refs., sampling, 393, Normal curve; Correlation,
395; law of error, 393. normal.
Rietz, H. L., refs., Handbook of — of variables, conditions as-Mathematical
 Statistics, 397. sumed in simple sampling, 335-Ritchie-Scott,
 A., refs., correlation 337; standard errors of percenof
 polychoric table, 390. tiles (median and quartiles), 337-Robinson,
 G., refs., Calculus of Obser- 341; dependence of standard
vations, 397. error of median on the form of the
Robinson, G. W., refs., error in soil distribution, 338-340; of differsurveys,
 396. : ence between two percentiles,
Romanovsky, V., refs., frequency- 341-343; of arithmetic mean,
curves, 393. 344-350 ; of difference between
Ross, Sir R., refs., frequency-curves two means, 345-346 ; normality
(epidemiology), 394. of distribution of mean, 346-347 :