Notices respecting New Books. 493 



Thus 



<NrW -. I [J-(l + i)f + (.*j + i)J 



o-^-.iBMi + J( ,+ 8}f + {i+K 1+ {) 



♦K 1+ l + »)}r--]- 



etc. 



University of Pennsylvania, 



Philadelphia, Pa., U.S.A. 



LVII. Notices respecting Neiv Books. 



Tables for Statisticians and Biometricians. Edited by 

 Prof. Karl Pearson. 9s. (Cambridge University Press.) 



THIS volume contains 55 tables and abacs, with an introduction 

 of some 83 pages giving particulars of their use. The tables 

 fall into three groups. The first group centres round the pro- 

 bability integral. If N is the total number of observations, m the 

 mean value, and z the frequency of an observation of magnitude x y 

 then 



N 



z= — - exp — (x — m) 2 /2a 2 , 



V27Va 



where a is a constant characteristic of the distribution. Pour 

 tables enable the reader to find any two of z, -, I zdx—- 1 z dx y 



Jx J— CO 



i. e. the ordinate, the abscissa, and the difference of the areas of the 

 two parts into which the ordinate divides the probability curve, when 



C x x l 

 the third is given. Other tables give I x n e ~ 2 dec, and enable 



Jo 

 the whole curve to be reconstructed from data concerning a portion 

 of it. 



The table for testing goodness of fit is founded on the above 

 normal law of error, and may be considered to belong to this group. 

 It deserves to be better known. Let//, f 2 ', f 3 ', . . . f n ' be observed 

 frequencies corresponding to x v x 2 , x 3 , . . . x n . Let z = <p(x) be a 



