vii.] DISCUSSION OF THE DATA OF STATURE. 93 



series in question refers to R.F.F. brothers, who, owing 

 to the principle on which the Table is constructed, are 

 only a comparatively small sample taken out of the 

 R.F.F. Population, and on a principle that gave greater 

 weight to a few large families than to all the rest. 

 Therefore it could not be expected to give rise to so 

 regular a Scheme for the general E.F.F. Population 

 as Table 11, which was fairly based upon the whole 

 of it. Less accuracy was undoubtedly to have been 

 expected in this group than in either of the others. 



Variability of the Population. — The value of Q in 

 the Statures of the general Population is to be deduced 

 from the bottom lines of any one of the Tables 11, 12, 

 and 13. The three values of it that I so obtain, are 

 1*65, 17, and 1*7 inch. I should mention that the 

 method of the treatment originally adopted, happened 

 also to make the first of. these values 1*7 inch, so I have 

 no hesitation in accepting 1*7 as the value for all my 

 ciara. 



Variability of Mid-Parents. — The value of Q in a 

 Scheme drawn from the Statures of the R.F.F. Mid- 

 Parents according to the data in Table 11, is 1*19 

 inches. Now it has already been shown that if marriage 

 selection is independent of stature, the value of Q in the 

 Scheme of Mid-parental Statures would be equal to its 

 value in that of the general Population (which we have 

 just seen to be 1*7 inch), divided by the square root of 

 2 ; that is by 1*45. This calculation makes it to be 



