Question about infinite probability?

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    Infinite Probability
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Discussion Overview

The discussion revolves around the theoretical implications of selecting an option from an infinite set of choices, particularly focusing on the probability of successfully picking a specific option given infinite time. The scope includes conceptual reasoning about probability distributions and the nature of infinite sets.

Discussion Character

  • Exploratory
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant questions whether it is physically possible to eventually select "option 1" from an infinite set of options, given the randomness of the selection process.
  • Another participant asserts that with infinite time, it is guaranteed to eventually pick "option 1," but this conclusion may not hold if the time is finite.
  • A different participant emphasizes that the actual probability distribution is crucial to answering the question, raising the need to clarify whether the infinite set is countable or uncountable.
  • One participant points out the issue of having a uniform distribution over a countably infinite set, stating that all probabilities would be zero, thus invalidating the scenario unless redefined as a limit problem.
  • This participant also notes the importance of specifying how the number of trials relates to the size of the set and whether selections are made with or without replacement.

Areas of Agreement / Disagreement

Participants express differing views on the implications of infinite time and the nature of probability distributions, indicating that multiple competing perspectives remain without consensus on the overall question.

Contextual Notes

Limitations include the need for clarity on the type of infinite set being discussed (countable vs. uncountable) and the specifics of the probability distribution and selection process, which remain unresolved.

NeptuniumBOMB
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i was just wondering (theoretically thinking), if I had to pick "option 1" from an infinite amount of options and my pick was random and I have an infinite amount of time (kind of like taking a ball from a bag, don't know which one is which) but I have to get exactly "option 1" and not any other.
Is their any physical chance that i will ever get the option i want or is it impossible because an infinite amount of options means that your probability is to small to exist?

Just wondering this, it isn't part of my homework or textbook.:biggrin:
 
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In general, if there are infinitely many events and you are considering the probability to select finitely many, then the probability is zero. Else way, it is the density of the set of selections in the set of events.

Given that you have infinite time though, you will absolutely pick option 1. Same goes with all other finite sets of options. If you had finite time, then we could not say the same.
 
Everything depends on the actual probability distribution. How likely is it to pick option 1??

Also, are you working with countable infinite or uncountable??

These things are needed to give a suitable answer to your question.
 
The trouble is you cannot have a uniform distribution over a countably infinite set. All probabilities would be zero, and the total probability would be zero, which is not valid.
You could redefine it as a limit problem as the size of the set tends to infinity. To complete the definition, you need to specify how the time (number of trials) available depends on the set size, n, and whether the ball is replaced after each trial. E.g. if you specify n trials, with replacement, the probability of success tends to 1 - 1/e.
 

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