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Thread: Percentage and probability

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    Percentage and probability




    I have this problem I am trying to solve and I am not sure how. Lets say 70% of the demography is white people. Now if I randomly pick 100 people from the same demography, how do I calculate what is the probability there are exactly 70 white people? or more general question, how do I calculate the chances that there are exactly X white people?

    Excuse me if this is a noob question.

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    Re: Percentage and probability

    You should investigate the binomial distribution. Although if you have a small population you should also look into the hypergeometric distribution.
    I don't have emotions and sometimes that makes me very sad.

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    informedman (05-29-2014)

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    Re: Percentage and probability

    Thats a great tip. If I use Bernoulli's probability mass function f(k;n,p), in the specific example above p = 0.7, k = 70, n=100?
    Last edited by informedman; 05-29-2014 at 08:35 PM. Reason: Misunderstood earlier

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    Re: Percentage and probability


    Quote Originally Posted by informedman View Post
    Thats a great tip. If I use Bernoulli's probability mass function f(k;n,p), in the specific example above p = 0.7, k = 70, n=100?
    Sounds about right to me.
    I don't have emotions and sometimes that makes me very sad.

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