i8o 
Journal of Agricultural Research 
Vol. XXVII, No. 4 
each quartile representing approximately one-fourth of the population. 
In order to determine the relation of height to production, the individual 
production of each plant was recorded in grams. The results are sum¬ 
marized in Table II and shown graphically in figure i. 
/70 
200 
2 3 
QCt4/?7V/.£rS 
Fig. i.—G raph showing average height of Yellow Dent corn plants, grouped in quartiles according to 
height, and average yield of plants in each quartile, respectively. Bloomington, Ill., 1919. 
Table II .—Data showing average height of 327 plants of Yellow Dent corn, grouped 
in quartiles according to height, 36 days after planting , and average yield of plants in 
each quartile , respectively , grown on brown silt loam soil of high fertility near Bloom¬ 
ington , III., IQ19 (see also fig. 1) 
Quartile. 
Num¬ 
ber of 
plants. 
Mean 
plant 
height. 
Mean 
plant 
yield. 
Increase in height (per cent). 
Increase in produc¬ 
tion (per cent). 
I. 
82 
Cm. 
116. 7 
137* 1 
150. 6 
169. 0 
Gm. 
142, 1 
175-6 
194.4 
179. 7 
2 . ... 
82 
Second quartile, 17.5... 
Third quartile, 9.8. 
Over first, 23.6. 
Over second, 10.7. 
Over third, —7.6. 
2. 
82 
0 
A . 
81 
Fourth quartile, 12.2.. . 
T. 
