Jan. 1,1925 
A Study of Variability in the Burt Oat 
49 
Table XI. — Data on association of class of floret disjunction and spikelet disarticu¬ 
lation m 9 strains of Burt oat grown at the Kansas Agricultural Experiment 
Station in 1920 
Spikelet disarticulation 
Strain number and kind of floret 
disjunction 
Number of kernels disarticu¬ 
lating by— 
Percentage of kernels dis¬ 
articulating by— 
Abscis¬ 
sion 
Semiab¬ 
scission 
Fracture 
Abscis¬ 
sion 
Semiab¬ 
scission 
Fracture 
Kansas No. 5020: 
Basifracture... 
75 
88 
105 
28.0 
32.8 
39 2 
Heterofracture - ^_ 
30 
16 
39 
35.3 
18.8 
45.9 
69.3 
Disarticulation. _,.. 
Kansas No. 5211: 
104 
292 
894 
8.1 
22.6 
Basifracture.. 
312 
124 
175 
51.1 
20.3 
28 6 
Heterofracture__ 
114 
48 
51 
53.5 
22.5 
24* 0 
Disarticulation.. 
373 
260 
602 
30.2 
21.1 
48 7 
Kansas No. 5219: 
Basifracture___ 
325 
302 
87 
45.5 
42.3 
12.2 
Heterofracture____ _ 
89 
62 
25 
50.6 
35.2 
14 .2 
Disarticulation__ 
323 
404 
287 
31.9 
39.8 
28 3 
Kansas No. 5220: 
Basifracture... 
41 
31 
58 
31.5 
23.9 
44.6 
Heterofracture. ... 
22 
8 
37 
32.8 
12.0 
55.2 
Disarticulation... 
38 
130 
514 
5.6 
19.0 
75 4 
Kansas No. 6004: 
Basifracture____ 
0 
5 
' 63 
0 
7.4 
92 6 
Heterofracture____ 
0 
1 
19 
0- 
5.0 
95 0 
Disarticulation... 
0 
12 
837 
0 
1.4 
98.6 
Kansas No. 6052: 
Basifracture___ 
0 
2 
74 
0 
2.6 
97.4 
Heterofractifre__ 
0 
0 
34 
0 
0 
100.0 
Disarticulation__I.. 
0 
19 
1,292 
0 
1.4 
98.6 
Kansas No. 6076: 
Basifracture..... 
0 
27 
62 
0 
30.3 
69.7 
Heterofracture..-.. 
0 
5 
7 
0 
41.7 
58.3 
Disarticulation__ 
0 
58 
836 
0 
6.5 
93.5 
Kansas No. 6090: 
. Basifracture__ 
162 
102 
49 
51.8 
32.6 
15.6 
Heterofracture.. 
32 
30 
18 
40.0 
37.5 
22.5 
Disarticulation_____ 
153 
275 
540 
15.8 
28.4 
55.8 
Kansas No. 6094: 
Basifracture... 
52 
54 
46 
34.2 
35.5 
30.3 
Heterofracture. 
11 
9 
7 
40.8 
33.3 
25.9 
Disarticulation___ 
115 
206 
381 
16.3 
29.6 
54.1 
All strains: 
Basifracture__ 
967 
735 
719 
39.9 
30.4 
29.7 
Heterofracture. -.. 
298 
179 
237 
41.7 
25.1 
33.2 
Disarticulation.. 
1,106 
1,658 
6,183 
12.4 
18.5 
69.1 
<?=0.672db0.003 
awnless, on the one hand, and as dark 
or light colored on the other. It is true, 
of course, that the coefficientof asso¬ 
ciation based on this grouping gives no 
information as to the relations between 
the individual phases of the two charac¬ 
ters. However, it is believed that the co¬ 
efficient of association determined in 
this manner does give a reliable index of 
the degree of association which exists be¬ 
tween the two characters. This method 
has been proposed and used in some¬ 
what similar though not exactly com¬ 
parable cases by Collins (21) and later 
by Kempton (57 ). By this methQd the 
complete independence of two character 
pairs is represented by 0 and complete 
association by, 1. Intermediate degrees 
of relationship are expressed by the in¬ 
termediate decimals. 
The probable errors of the coefficients 
of association as given in the text and 
in Tables XI to XV were determined 
by substituting Q for r in the following 
formula: 
™ 0.6745 (l-r 2 ), 
J^r 7= 
Vw \ 
which is the one generally used for 
computing probable errors of correla¬ 
tion coefficients. While the yalues thus 
obtained are admittedly only approxi¬ 
mations, it is believed that they do not 
deviate from the true values for the 
probable errors of Q any more than, if 
as much as, the values for Q itself differ 
from the values for r. The relations of 
these two constants are shown in the 
following table from Yule (152). 
