Sounds to me like people are arguing from the same side of the fence. The question as first posted was badly phrased. That later part of Eddy-B's post is exactly what I took the question to mean after the answer was given. Before the answer was given, I also stated 50%. After the answer was given, I realized the question was poorly worded, and attempted to rephrase it to make the meaning he intended clear. A number of restastements were posted in this thread, and people seem to be arguing about two separate questions now.
In my last restatement:
A woman has 2 children. What are the chances of both of them being a girl, given that at least one of them is a girl?
I meant precisely that woman was taken from a restricted sample space. Hence the "given" part with the extra info to restrict you to that sample space. The "a woman" part largely being used to mean we are choosing one person from that sample space.
But yes, the way you just stated it Eddy makes it much more clear.
This thread seems to have become more of a debate over English semantics than probability or statistics.
Simpsonboy, I have no idea what you said in your last paragraph, and I think you need to check that over.
Edit: Err, Eddy, did you just lock the thread?
