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# S1- Discrete Random Variables watch

1. Ok, I have this question:

the probability is in the table below:

x P(X=x)
1 0.1
2 0.2
3 0.3
4 0.3
5 0.1

b) Given that X1 and x2 are independent observations on X, calculate
P(X1=X2)

Could someone explain simply how you would do this. thanks
2. It's been a while since I've done stats, but wouldn't it just be a case of finding out the probability of getting the same number twice for 1 thru 5 then adding the probabilities up?

Ie 0.1*0.1 + 0.2*0.2 + 0.3*0.3...

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Updated: February 10, 2010
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