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# Discrete uniform distribution

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1. When working out E(X) of a DUD you need to use use (n+1)/2. What does 'n' represent in this formula?
2. I would just use the way you're taught, as in sigma xP(x), the (n+1)/2 only works for a distribution that starts at 1 and has n terms.
For example for a fair dice E(X) = (6+1)/2 = 3.5, although I'd still do 1/6*1 + 1/6*2 etc, just to show all your working
3. (Original post by JN17)
I would just use the way you're taught, as in sigma xP(x), the (n+1)/2 only works for a distribution that starts at 1 and has n terms.
For example for a fair dice E(X) = (6+1)/2 = 3.5, although I'd still do 1/6*1 + 1/6*2 etc, just to show all your working
ok thank you.

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