VARIABILITY OF A SINGLE CHARACTER 119 



M 



M = 6. 1 2 1 M = 6.304 ^ ^ 



V — 0.530 a — 0.579 <r = 0.499 

 C = 8.66 C = 9.ir '' ^ 



18 C 



6.505 

 :o.49< 



: 6.90 



M = 17.91 1 M = 18.107 M = 16.869 

 <r= 2.501 ff= 2.417 <r= 2.377 

 C = 13.96 C = 13.35 C = 14.09 



Original problems. Besides the solving of distributions given 

 in the text, the student should have practice in devising and 

 solving problems of his own. I know of no better method of 

 teaching variability, and at the same time insuring rational 

 conceptions of heredity, than by this methodical and accurate 

 study of characters taken singly. 



For this purpose the student may use not only dimensions 

 like length and circumference, but he may use weights and num- 

 bers. He may take the heights of pupils in the school, the 

 grades they make in classes, or he may take the yield of milk 

 of many cows, or the weights of milk at the creamery. Anything 



* Experience 8how.s that it is better to take values by 0.25 instead of 0.30 ; 

 thus, 4.50, 4.75, 5.00, 5.25, etc. These distributions were made smooth only 

 by careful assignment of alternate measurements. This scheme of grouping 

 has been discarded for this reason. 



^ Below each/ column will be found the corresponding values. Thus of the 

 first frequency, footing 310, the M = 6. 121, the <r = 0.530, and the C = 8.66. 

 In this way the answers can be identified for each problem contained in these 

 tables. 



