1374 
In making up the protocols we determined: 1° the time taken up 
by the test, a fraction of a minute being eliminated; 2° the total 
number of mistakes. We considered as mistakes: a letters which 
should bave been struck out and were skipped; 6 letters that were 
struck out by mistake. The mistakes sub a and 6 were added up. 
Finally the mistakes made in every minute were cast up shia sub 
a and 6 also put together). 
Table I shows the time required for the test by the children of 
various ages, boys and girls together and each sex separately. The 
first column gives the arithmetical means (A. M.); the second the 
mean deviations (M. D.) and the third the central values (C. V.). 
TABEE 
Age (years) Boys Girls | Children 
on AMD Efe _ [AM | MD. | CV. | aM MD, CV. | AM | MD. | CV AM. | M.D. | GY. 
14 Tel ie | 14 
13.39] (2.3 13 
[StS SAM 13 12527202 12 
RAD ses 12 eZ enna 11 
antenne 13 16 AEN 1) 
10 11 2 11 
10 EE Bia, AL NP 10.5: ed Onan 
| | 
From this it appears that for boys and girls together, as well as 
for the two sexes separately, the time required for the labour de- 
creases with the increase of age, leaving aside one exception: the 
boys of 12 years. (The average decrease from 8—12 years is about 
30 °/,). It should be observed that the working-times of the girls 
are invariably longer than those of the boys. As to the amount of 
work done in a certain time the boys are in advance of the girls 
by two years: the mean working time of the boys of 8 years is 
only little more than that of the girls of 10, while the mean time 
of the boys of 10 is exactly equal to that of the girls of 12. These 
data are substantiated by the mean deviation, which in all cases is 
at most '/, of the arithmetic mean, and by the fact that the central 
values are invariably equal to or smaller than the arithmetic means. 
That the mean deviation lessens with the increase of years points to 
the fact that with the increase of years a decrease is observable of 
the individual differences regarding the working-speed in various 
types of life-time. 
