Hypothesis
| 9:7
hypothesis |
3:1
hypothesis |
| class |
dominant |
recessive |
Total |
domiant |
recessive |
| obs. |
63 |
32 |
95 |
63 |
32 |
| exp |
53.44 |
41.56 |
95 |
71.25 |
23.75 |
X2=(63-53.44)2+(32-42.56)2
53.44 41.56
|
X2(63-71.25)2+(32-23.75)2
71.25 23.75
|
=
1.710 + 2.199
= 3.91
reject 9:7 |
=
0.955 + 2.866
= 3.82
accept 3:1 |
Even with the worst case scenario of the observed numbers having the
ambiguous ratio, we can still distinguish between the
two hypothesis when n=95.
If we use n=95 and calculate the expected number of recessives for
each of the two hypothesized ratios, we get:
Ho:3:1 
1/4(95) = 23.75~24
Ho:9:7
7/16(95) = 41.6~42
The mean is (42+24)/2 = 32. Therefore when n =95 and we have more than
32 recessives we would accept the 9:7 ratio. If we have fewer than 32
recessives we would accept the 3:1 hypothesized ratio.
