THE STATISTICAL STUDY OF VARIATION 



33 



individual beans varied considerably in size. Furthermore if one were 

 to obtain the average weight of the whole million, it would not differ, 

 essentially, from the average weights of the smaller groups. The prin- 

 ciple involved here may be stated in various ways. Weld expresses it 



M 



= 15.4 



10 II 13. 15 1+ 13 l(> 17 19 l<f il 1.3. 



FIG. 14. Frequency distribution of 500 Broad Beans arranged in classes according to 



width. 



as follows: "// a number of different events are equally possible as regards 

 constant conditions (that is, if there is no persistent reason why one should 

 occur rather than another), and all are repeatedly given opportunity to 

 occur, they will in the long run occur with equal average frequency." While 

 this is a satisfactory general statement of the law of probability, the same 



