W. R. Macdonell 
207 
and the probable error 
•67449 
P 
(See Pearson, Fhil. Trans. Vol. 192, A., pp. 171-2.) 
(18) In our case A is the determinant of the 7th order 
1- 
•40163 
•39454 
•30071 
•30539 
•33886 
•33993 
•40163 
V 
•61779 
•15040 
•13515 
•20614 
•18308 
•39454 
•61779 
V 
•32097 
•28869 
•36322 
•34527 
•30071 
•15040 
•32097 
1^ 
•84638 
•75871 
•66084 
■30539 
•13515 
•28869 
•84688 
1^ 
•79699 
•79986 
•33886 
•20614 
•36322 
•75871 
•79699 
1- 
•73636 
•33993 
•18308 
•34527 
•66084 
•79986 
•73636 
1^ 
the value of which is found by the laborious process of reduction to be = •012129. 
Also 
Ell = 
•016272 
and V'A/R„ = 
•86336 
-R22 ~ 
•020907 
•76167 
•022556 
Va/7?73 = 
•73330 
E44 = 
■047496 
^^|R^ = 
•50534 
= 
•071864 
•41083 
•^"66 = 
•040198 
•54930 
R77 = 
•038347 
VA/is:,7 = 
•56240. 
Now the best organ to leave to the last will be that the variability of which is 
least reduced by selecting the other six. For this means that the individuals 
from whom we have in the last instance to select our man, will be least crowded 
together and therefore least likely to be indistinguishable. As « = o- ^y/ ^ , the 
greater , the less the reduction in variability ; this function we have 
already calculated for n — 7, and we see that in that case it is greatest for Head 
Length. We will therefore keep Head Length to the last, and proceed to 
calculate sj ^ ^'^^ organs that remain after the elimination of Head 
Length. The new A is obviously i^n = "016272, and the new Rs can be calculated 
without much trouble. On comparing the new /y/ series, we shall find that 
Head Breadth is the next character to be eliminated, and we proceed in like 
manner until we have dealt with all the characters. 
* Values of the correlation coefficients are given to 5 places of figures in order to calculate the 
determinants more accurately. 
