Aug. 18,1923 
Inheritance of Dwarfing in Maize 305 
CORRELATIONS OF MEASURED CHARACTERS 
The character of the distributions in most cases precludes the use of 
the correlation coefficient, since the measured character so often is bimo- 
dal. Recourse may be had to fourfold groupings, dividing the population 
arbitrarily into two groups of the measured character, but when such 
Fig. 4.—Frequency distribution for width of leaf. Shaded portion, dwarf plants; solid lines, brachytic 
plants; broken lines, normal plants. 
divisions are made with due regard to the character of the distributions 
one class is often zero or very small. Under such conditions a correlation 
coefficient is practically without meaning, and such coefficients have not 
been calculated. In those cases where the data justified the use of the 
biserial correlation, the coefficients have been calculated and are given 
in Table V. For the most part, however, the frequency polygons will 
give a clear conception of the nature of the inheritance. 
