Originally Posted by

**awkward** fschmidt,

I disagree with you there. True, the probabilities would change if you knew what coins were previously chosen, but you don't. Or if you were interested in the total number of quarters chosen, Z would be relevant-- but that isn't the question which was asked.

To get away from quarters for a moment, suppose you have a bag with 10 red balls and 20 black balls in it. Select a ball at random and put in a cup. What is the probability that it is red? 1/3. Or select all 30 balls and put them in the cup. Then select a ball at random from the cup. What is the probability it is red? 1/3.

Sure you don't want to describe your original problem to us? The fact that we are having this discussion makes me think that you may be interested in more than the simple probabilities.

jw