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Thread: Binomial question

  1. #1
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    Binomial question




    Hi,

    I have attached a binomial question in excel (question & solution).

    In part (e), the question asks for the P(between 5 and 15 inclusive)
    The answer in cell B22 is:
    0.9577 =BINOMDIST(15,B3,B4,1)-BINOMDIST(4,B3,B4,1)

    Could you please explain why the solution refers to BINOMDIST(4,B3,B4,1) and not BINOMDIST(5,B3,B4,1)? i.e. why 4, not 5?

    Thanks,
    --Peter
    Attached Files

  2. #2
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    Re: Binomial question


    I couldn't open your file because I have a real old version of excel, but the last variable "1" makes the result cumulative.

    So BINOMDIST(15,B3,B4,1) = P(X=0) + P(X=1) + ... + P(X=15)

    And BINOMDIST(4,B3,B4,1) = P(X=0) + P(X=1) + ... + P(X=4)

    So BINOMDIST(15,B3,B4,1)-BINOMDIST(4,B3,B4,1) = P(X=5) + P(X=6) + ... + P(X=15)

  3. The Following User Says Thank You to asterisk For This Useful Post:

    pcampin (01-03-2014)

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