How to interpret this probability

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    Probability
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Discussion Overview

The discussion revolves around the interpretation of probability and the calculation of expected values for a set of equally probable integers from 1 to N. Participants explore the concept of statistical averages and the mean of a random variable.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant asks how to find the expected value E[n] for integers 1 through N, suggesting that the statistical average of a number is the same as the number itself.
  • Another participant interprets the question as seeking the average of a random variable X, which takes values from 1 to N with equal probability, stating that E(X) = (1+N)/2.
  • A later reply clarifies the original question, indicating a need for the mean of each individual number rather than the average of the random variable.
  • One participant asserts that the mean of a constant is simply the constant itself, suggesting a misunderstanding in the original question.
  • A final post acknowledges a correction, indicating that the initial interpretation of the question was incorrect and reiterating the nature of n as a random variable with discrete values.

Areas of Agreement / Disagreement

Participants exhibit disagreement regarding the interpretation of the original question, with some focusing on the expected value of a random variable while others emphasize the mean of individual constants. The discussion remains unresolved as participants clarify their positions without reaching a consensus.

Contextual Notes

There are limitations in the clarity of the original question, leading to different interpretations. The discussion reflects varying assumptions about what is meant by the "mean of each number" and the nature of the random variable involved.

EngWiPy
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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?

Thanks in advance
 
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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.

If I misunderstood your question, please clarify.
 
mathman said:
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.

If I misunderstood your question, please clarify.

No, I need the mean of each number.
 
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
 

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