|
|
X2 Tests For F2 Data
Test
Ho:9:3:3:1 ratio overall w/3 df
Ho:3:1 ratio for A locus w/1df
Ho:3:1 ratio for B locus w/1df
Ho:A and B are independent w/1df
Ho:homogeneity X2
for each X2
above
Example: F
test for linkage
| Family |
A_B_ |
A_bb |
aaB_ |
aabb |
Total |
| 1 |
47 |
8 |
11 |
9 |
75 |
| 2 |
75 |
14 |
14 |
11 |
114 |
| 3 |
65 |
13 |
12 |
11 |
101 |
| Totals |
187 |
35 |
37 |
31 |
290 |
For totals: Ho:9:3:3:1
xT2 = |
16(a12 + 3a22 + 3a23 + 9a4)2 - n |
|
|
| 9n |
|
|
| |
|
= |
16[(187)2 + [3(35)2] + [3(37)2] + [9(31)2] - 290 |
9(290) |
| |
|
= |
16(34969 + 3675 + 4107 + 8649) - 290 |
|
2610 |
|
| |
|
= |
25.095 w/3df reject Ho:9:3:3:1 |
|
X2A = |
(a1 + a2 - 3a3 - 3a4)2 |
3n |
= |
[187 + 35 -3(37) - 3(31)]2 |
3(290)
|
= |
324 |
= 0.372 w/1df accept Ho:3:1 |
870 |
X2B = |
(a1 - 3a2 + a3 - 3a4)2 |
3n |
= |
(187 - 105 + 37 - 93)2 |
870 |
= |
676 |
= 0.777 w/1df accept Ho:3:1 |
870 |
X2L = |
(a1 - 3a2 - 3a3 + 9a4)2 |
9n |
= |
(187 - 105 - 111 + 279)2 |
2610 |
= |
62500 |
= 23.946 w/1df reject Ho: independence
between loci |
2610 |
Copyright
2000©, Ted Helms
|
|
