# Help with simple probability question!! Excellent question.

Discussion in 'Statistics' started by Duke Morrison, Sep 20, 2004.

1. ### Duke MorrisonGuest

Q: In a certain species of rats, black dominates over brown. Suppose
that
a black rat with two black parents has a brown sibling.
(a) What is the probability that this rat is a pure black rat
(as opposed to being a hybrid with one black and one
brown gene)?
(b) Suppose that when the black rat is mated with a brown
rat, all five of their offspring are black. Now, what is the
probability that the rat is a pure black rat?

An answer to this question would be greatly appreciated... I have a
hunch that the answers are 1/3 and .94 but cannot fully confirm
this... they could be wrong. If anyone has a descriptive of any sort
i'd be very grateful. Thank you!

Duke Morrison, Sep 20, 2004

2. ### Duke MorrisonGuest

Please do not bother with answering this question as I have now
confirmed my answer properly. But thanks to all those who took the
time to read it anyways. =]
The answer is indeed 1/3 and .94 for all those interested.

Duke Morrison, Sep 21, 2004