486 
On the Problem of Sexing Osteometric Material 
personal equation, depending on the features upon which the experience of the 
individual anatomist leads him to lay most stress. The solution (C) is unique, 
that is to say, given the same data, all statisticians would reach the same values, of 
Frequency Distributions of Bicondylar Width in Male and Female Femora 
sexed by Anatomical Appreciation. 
mm. 
? 
6 
mm. 
? 
6 
inm. 
? 
6 
61 
1 
71 
20-5 
2-5 
81 
28 
62 
1 
72 
29-5 
4 
82 
23 
63 
1-5 
73 
16 
9 
83 
19 
64 
5 
74 
11-5 
10-5 
84 
1 
16-5 
65 
13-5 
75 
10 
26 
85 
19-5 
66 
14 
76 
7 
18-5 
86 
16-5 
67 
15-5 
77 
2-5 
27 
87 
7-5 
68 
22 
78 
1 
31 -5 
88 
3 
69 
31 
79 
1 
18-5 
89 
3-5 
70 
15-5 
3-5 
80 
1 
32 
90 
0-5 
course apart from errors in arithmetic or from the number of decimal places 
retained in the working. It eliminates the factor of personal equation. 
(ii) (C) would, however, be influenced by the fact that our material is not 
perfectly hom.ogeneous except for sex ; because (a) there is a mixture of right and 
left bones, and, to judge by the anatomical sexing, this may involve a difference of 
"7 to "9 mm. in the means and "08 to "24 mm. in the standard deviations ; this 
would add to the heterogeneity, (b) our bones may be due to somewhat mixed 
classes aud possibly mixed periods, (c) the bicondylar width is liable to be injured 
by rough treatment of the bone, and this injury will most affect the weaker, and 
therefore probably the younger, bones. These bones might then be treated as female, 
a classification which inost anatomical sexing also favours. While the total number 
of these London femora is nearly 800, the bicondylar width could only be measured 
in 541 cases. This selection will not necessarily be random as to size or sex, 
and may modify our constants found mathematically from the distribution. On 
the other hand it would affect also the anatomical appreciation of sex, but only 
in as far as it was based on the size of the condyles. 
(iii) We know from very considerable sexed data that the variation of man 
and woman is very nearly the same. The coefficients of variation measured in the 
usual way, i.e. by 100 standard deviation divided by mean, gave: 
Mathematical Sexing. 
? 4-92 ^ 4-57 
A = -35 
Anatomical Sexing. 
? 5-01 5-17 
A = - IG 
