OK ATTR1BITKS IN STATISTICS. 319 



fraternity the number of A A, Ace, a A, and aa pairs, as in the example on " Temper 

 in Fraternities," p. 291, aiul tabulate the total number of such separate pairs as in 

 that example. These numbers give the association between brothers at once. 



A certain portion of such fraternal association might be due to similarity of 

 environment for the brothers, if the defects observed were much affected by this. 

 I do not see how the home-environment could be allowed for, but it could be tested 

 whether the environment of school had any such effect. Take from a considerable 

 number say 100 different schools a series of samples, say 50 or 100 children 

 from each. Each of these groups forms what we may call a " community " or 

 group subjected to common conditions, as opposed to the fraternity. Find the 

 association between members of the Community in just the same way as the 

 association between members of the Fraternity. This would give a measure of the 

 effect of environment as opposed to inheritance. Possibly this might be done with 

 the material now in the hands of the Society. 



