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I don't get this.... can someone please explain.
If there is n beads in a bad, and 6 of them are black, then I can understand that the probability of removing a black one is
. If the rest of the balls in the bag are white, then I can understand that the probability of removing a white ball is . But if you take a white ball out, without replacement, will there be balls left in the bag, and why? I just can't visualise what is going on.Thanks.
Last edited by Daniel123 (2007-06-02 00:40:08)
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It'll be
.Before, there were n-6 white balls out of n balls altogether. If you remove a white ball then both of those counts decreases by 1. So there are (n-1) balls, (n-7) of which are white.
You can see that is has to be this way by thinking about what would happen if you had removed 6 white balls without replacement instead of just the one.
Why did the vector cross the road?
It wanted to be normal.
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Right ok I get it now. Thanks
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