On 2011-11-06, Ed Huntress wrote:


"Ignoramus27678" wrote in message
...

On 2011-11-06, Bob Engelhardt wrote:
Given: an opaque jar with a large number of white & black marbles, same
number of each. If I pick 2 marbles randomly, it seems that the
probabilities depend upon how I do the drawing.

If I pick one marble, then pick another, the probability of drawing one
black and one white marble is 50%. (4 possibilities, 2 of which give 1
white & 1 black.)

If I reach in and pick 2 marbles AT ONCE, the probability is 33%. (3
possibilities, 1 of which gives 1 of each color.)

3 possibilities, unequal probabilities.

Your reasoning is wrong.

i\

Jeez, you're harsh. d8-) Why don't you explain that the two possibilities of
one each black and white, in the first example, actually give the same
result and are really just two different orders for the *same*
possibility -- one white, one black?

Inelegant, but maybe helpful...


I am sligfhtly drunk, I did not mean to be harsh or rude, sorry.

i