Io6 DOMESTICATED ANIMALS AND PLANTS 



Distribution as to 

 Length 



Then measure each ear and record it opposite the figure in 

 the scheme that comes nearest to the correct measure of the 

 ear. When all the ears have been measured and the lengths 

 recorded, you will have results similar to these of the follow- 

 ing table, which is an actual case taken from a field of Reed's 

 Yellow Dent, crop of 1906. 



By this we see that in all 286 ears were 

 measured ; that our scale was longer 

 than it needed to be, for no ear was 

 found as short as 4 inches or as long as 

 12 inches; that one ear was 5 inches 

 long, four were 5^ inches long, etc. ; and 

 that the number gradually rises to 59 and 

 then as gradually declines, so that ex- 

 tremes of length are represented by rela- 

 tively few ears. 



Types. We are ready now to arrive at 

 a rational conception of type. The most 

 common length of ear is not 5 inches nor 

 is it 10 inches, but it is 8 i^ inches, because 

 59 out of 286 ears were nearer that length 

 than any other. This is therefore the most 

 usual, or, as we say, the typical length. 

 This is not saying that it is the most de- 

 sirable length, but that it is the length 

 most commonly found. ^ Such a value is 

 called the mode, and we say that 8.5 inches is the mode of 

 this corn as to length. 



Plotting the frequency curve. Such a lot of measurements 

 is technically called a '' frequency distribution" or, more briefly, 

 a " distribution." It is always indicated by the letter /, as is 

 the scheme of values by the letter V. 



1 That is, a blindfolded man drawing ears at random would draw this length 

 oftener than any other ; or if one's life depended upon a single draw, he would 

 stand more chances by drawing this than any other length. 



