Probability of an event occurring at least once over n trials

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Discussion Overview

The discussion revolves around calculating the probability of an event occurring at least once over multiple trials, specifically in the context of Joe contracting an STD during sexual encounters. The scope includes mathematical reasoning and homework-related inquiries.

Discussion Character

  • Homework-related
  • Mathematical reasoning

Main Points Raised

  • One participant states that there is a 1 in 4 chance of contracting an STD during a sexual encounter and poses a question about the probability of contracting an STD after 4 encounters.
  • Another participant suggests considering the probability of not contracting an STD after 4 encounters as a hint for solving the problem.
  • A participant proposes a calculation method: 1 - (0.75 * 0.75 * 0.75 * 0.75) to find the probability of contracting an STD at least once, which is acknowledged as correct by another participant.
  • One participant inquires about calculating the probability of contracting an STD exactly twice out of the 4 encounters, suggesting that combinations may be necessary for this calculation.

Areas of Agreement / Disagreement

Participants generally agree on the method for calculating the probability of contracting an STD at least once, but the inquiry about contracting it twice introduces uncertainty and remains unresolved.

Contextual Notes

The discussion includes a potential misplacement of the question in the forum, as it is noted to be a homework-type question. There may be limitations in the assumptions made regarding the independence of trials and the specific conditions of the problem.

helpmeplzzz
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There is a 1 in 4 chance that on any given sexual encounter, Joe will contract an STD. If Joe has sex 4 times, what are the chances of him having an STD?
 
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Hint: what is the probability of not contracting after 4 times?
 
1-(.75*.75*.75*.75) = my answer?
 
Looks good.
 
So how would you do it for the probability of Joe contracting an STD twice out of those 4 occasions?

I think you would have to do a combination for this?
 
As this is misplaced homework-type question, I am locking it. This thread was also posted in the Precalc section under Homework & Coursework.
 

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