Binomial Distributions Part IV
Example
x = y = 1/2, n = 8, r = 7
| n! |
(x)r (y)n-r |
|
|
| r!(n - r)! |
|
|
| = |
8! |
( |
1 |
)7 |
( |
1 |
)1 |
| 7!1! |
2 |
2 |
| = 8 ( |
1 |
)( |
1 |
) = |
8 |
| 128 |
2 |
256 |
We could use this formula to find the probability of
six Aa and two aa progeny in a family of size eight.
n = 8, r = 6, n-r = 2, x = 1/2, y = 12
P(six Aa, 2aa) =
| (x)r (y)n - r = |
8! |
( |
1 |
)6 |
( |
1 |
)2 |
| 6!2! |
2 |
2 |
| = |
40320 |
( |
1 |
)8 |
|
|
|
| (720)(2) |
2 |
|
|
|
