32n 



THE AMEBIC AN NATURALIST [Vol. XL V 



of mathematics beyond algebra up to the binomial theorem is 

 presumed, yet the subject is developed in such a simple, lucid 

 and at the same time thorough way as to give the reader a real 

 and adequate grasp not only of the technique of the methods, but 

 also of their origin and significance. Numerical examples drawn 

 from a wide range of materials are given at every stage and 

 worked out in detail. Particular attention is paid to guiding 

 the unwary beginner around the numerous pitfalls which beset 

 the statistical pathway. Chapters are devoted to the methods 

 of arranging data in the form of frequency distributions, deter- 

 mining centering constants (arithmetic, geometric and harmonic 

 means, mode, median, etc.), variation or "dispersion" measuring 

 constants, and coefficients of correlation. The treatment of cor- 

 relation is particularly comprehensive and practical. 



The last section of the book deals with the general subject of 

 "probable errors." The theory of fluctuations in statistical 

 measures due to random sampling is developed first in relation 

 to the theory of attributes and then in relation to the more com- 

 plex theory of variables. The discussion of the simple sampling 

 of attributes leads up in a straightforward 



and the 



correlation surface. 



Each chapter throughout the book is followed by a short list 

 of selected titles of original papers, and a series of practical 

 problems to be worked out by the student. Appendices give 

 short bibliographies of calculating tables, tables of functions, etc., 

 and general works on the mathematical theory of statistics and 

 the theory of probability. A list of answers and hints in regard 

 to the problems and a full index complete the volume. 



Altogether the book is a notable one. Those who are familiar 

 with Yule's paper "On the Theory of Correlation" (published 

 in the Journal of the Royal Statistical Society in 1897) which 

 has become one of the classics of biometric literature will be 

 prepared to welcome the present work. It is marked throughout 

 by the same clearness, directness and appreciation of the diffi- 

 culties of the beginner which distinguished that memoir. For 

 the non-mathematical student desirous of obtaining a sound 

 working knowledge of the elements of modern statistical theory 

 this book will be of the greatest value. In the field which it 

 covers it is without a peer. 



