30 Variation and Correlation in Brain-Weight 
TABLE V. 
Difference in Variation Constants between " Young" and "Total" Series. 
? 
S. D. 
C. of V. 
S. D. 
0. of V. 
Swedes 
+ 2-851 + 4-066 
+ •122 + -291 
+ 4-786 ±5-465 
+ •271 + -435 
Hessiaus ... 
-1-347 + 3-971 
- -177 + -285 
- -527 + 4-541 
-■170 + -372 
Bavarians 
-1-888 + 3-556 
- -173 ±-234 
-10-357 + 3-909 
- ^941 + -320 
Bohemians 
+ -787 + 4-371 
+ -026 ±-304 
- 3-545 + 5-067 
- -287 + -388 
(Skull)* 
+ 1-832 + 4-230 
+ -078 + -295 
- 1-932 + 4-866 
- -206 +-372 
Difference + when "Young" is greater. 
In only one case — the Bavarian females — is the difference as large as its 
probable error, and in this case the difference is not three times the probable error. 
The conclusion seems justified that the series are reasonably homogeneous in other 
respects than age. The age distribution is such as to exclude growth effects, and, 
as the differences indicate, the effects of senescence on brain-weight are so insig- 
nificant that for practical purposes the material may be considered sufficiently 
homogeneous to warrant further biometrical study. From the character of the 
differences it would appear that the most homogeneous series are, on the whole, 
the Swedish and the Bohemian. 
A direct examination of the standard deviations and coefficients of variation 
confirms the conclusion. In the following table I have arranged in order according 
to ascending value, the variation constants for the " total " series, using as the 
basis for the grouping the coefficient of variation : 
TABLE VI. 
Comparison of Different Races in Respect to Variation in Brain-tveight 
and Skull Capacity. 
Males 
Females 
S. D. 
0. of V. 
S. D. 
0. ofV. 
Swedes ... 
106 ^329 
7-592 
Bohemians 
96-772 
7-382 
Bohemians 
113 •eos 
7-809 
Swedes ... 
100-757 
8-043 
Hessians 
112^675 
8-096 
Hessiaus 
102 ^368 
8-125 
Bavarians 
110-664 
8-118 
Bavarians 
10r776 
8^340 
English t 
124-48 
9-20 
English t 
118^7 
9-72 
Skull Capacity, English I 
8-28 
Skull Cajjacity, English J 
8-68 
,, ,, Germans § 
7-74 
,, „ Germans § 
8-19 
* See p. 17 and Table I. for the series here referred to. 
t Pearson : The Chances of Death, Vol. i. p. 321. 
t W. E. Macdonell: Biometrika, Vol. iii. p. 221. 
§ Pearson : The Chances of Death, Vol. i. p. 333. 
