# How to interpret this probability

## Main Question or Discussion Point

Hi,

If we have N numbers, say 1,2,3,...,N which are all equally probable, then how to find E[n], for n=1,2,...,N? I mean the statistical average of a number is the same number, right?

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mathman
As I understand your question, you are looking for the average of a a random variable (X) which can assume integer values from 1 to N, each with probability 1/N. The answer to that questions is E(X) = (1+N)/2.

As I understand your question, you are looking for the average of a a random variable (X) which can assume integer values from 1 to N, each with probability 1/N. The answer to that questions is E(X) = (1+N)/2.

No, I need the mean of each number.

lanedance
Homework Helper
you question doesn't make a heap of sense, trivially the mean of a constant c, is the same as the constant E[c] = c

Yes right. mathman was right, and I was wrong. n is a random variable that takes on discrete values of equal probabilities.

Regards