Probability!choose without replacement!

evinda

Junior Member
Joined
Apr 13, 2013
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57
We have a container that contains r balls that have numbers 1,...,r. We choose at random n of them without replacement. Let Y be the greatest and Z the smallest of the numbers of the balls we chose. Which are the probabilities P(Y<=y) and P(Z>=z)????
Thanks in advance!!!!
 
We have a container that contains r balls that have numbers 1,...,r. We choose at random n of them without replacement. Let Y be the greatest and Z the smallest of the numbers of the balls we chose. Which are the probabilities P(Y<=y) and P(Z>=z)????
Thanks in advance!!!!
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The number of ways to pull two balls just from 15 is 15*14/2 = 105.The number of ways you can pull two balls from 20 balls is 20*19/2 = 190.So the probability is 105/190?????Is this correct????
 
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