No. 539] DISTRIBUTION OF PURE LINE MEANS 693 



are less than unity, while for all the mean is .936. On 

 an average, therefore, the pure lines have 93.6 per cent, 

 as much variability as the population. 



The second comparison, that between the variability 

 of the individual pure lines and the population which 

 they form, can be made on the basis of the standard 

 deviations alone since the means are the same. This 

 comparison (the last two columns of Table IT) shows 

 that in both series and for every character the variabil- 

 ity written, the line is less than that for the population. 

 The lowest ratio is .70, the highest is .92 and the mean 

 is .858. This test indicates that they are differentiated. 

 This is, of course, the conclusion which Roemer drew 

 from his selected individual comparisons. 



Second Test. The Deviation of the Pure Line Means 

 from the Population Mean 

 For characters measurable on a quantitative scale the 

 test for the deviation of the offspring of an individual 

 from its population is given by 



Where m and M, <r and 2, n and N are the means, stand- 

 ard deviations, and numbers of individuals for the 

 family and the population, respectively. 11 



For reasons which will be apparent to the reader 

 later, the data which are given us do not justify calcu- 

 lations to a high degree of refinement. 12 We therefore 

 approximate in every point possible. 



The expressions 



