Karl Pearson 
103 
For tonsils : 
^(1- a) = -2679, HI + «) = ■' 321, ^ = •3293. 
Correlation of good glands and weight = g!^g^^2 ^ .3933 
= •070. 
Correlation of good tonsils and weight = x Jf^^ 
= -076. 
Thus bad glands and tonsils are slightly, but I think significantly associated, 
with less weight in the child. The correlations are not, however, as large as we 
might a priori have anticipated that they would be. 
Illustration V. Effect of the Employment of Mothers on the Height of their 
Children. I owe the data on this point to Miss E. M. Elderton, who has been 
working on the Glasgow School Board Returns. The first table gives the age of 
sons for mothers employed and not employed ; the second gives the height of sons 
for mothers employed and not employed. I take it that the categories employed 
and not employed correspond to a continuous variable, which for want of a better 
name, I may term, stress on mother. Practically all these mothers may be said to 
have their household work. In some cases — apparently relatively few in Glasgow 
— they do other work of a variety of kinds. This extra work must increase the 
claims on the mother's energy, and we might expect it to show in the physical 
welfare of the child. This point will be fully discussed by Miss Elderton in her 
forthcoming memoir. I only use the data here as illustration of the new method. 
Employment of Mothers and Age of Sons. 
Age of Sons 
Mothers, Employed 
Mothers, not 
Employed 
Totals 
4-5— 5-5 
48 
942 
990 
5-5— 6-5 
185 
3137 
3322 
6-5— 7-5 
247 
3656 
3903 
7-5— 8-5 
253 
3947 
4200 
8-5— 9-5 
263 
3754 
4017 
9-5— 10-5 
242 
3639 
3851 
10-5— 11-5 
186 
3575 
3761 
11 -5— 12-5 
204 
3428 
3632 
12-5— 13-5 
187 
3451 
3638 
IS -5— 14-5 
45 
1422' 
1467 
Totals ... 
1860 
30951 
32811 
Mean age of all Boys = 9 5563. 
Standard Deviation of all Boys = 2-4806. 
Mean age of sons of employed mothers = 9"3790. 
1(1 -a) = -0567, ^(1+ a) = -9433, 2 = -1139. 
•1773 -0567 
~ 2-4806 ^ -1X39 
vT«^ = - -0356. 
