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Math Help - Expressions for Binomial Distributions

  1. #1
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    Expressions for Binomial Distributions

    Hi i am working on a Binomial Distribution

    If i know the Mean of A is 7.6

    and

    I know the Variance of A is 5.48

    How do you write an expression that A >= 28?
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  2. #2
    Grand Panjandrum
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    Quote Originally Posted by davidrocastle View Post
    Hi i am working on a Binomial Distribution

    If i know the Mean of A is 7.6

    and

    I know the Variance of A is 5.48

    How do you write an expression that A >= 28?
    Mean = Np

    Variance =Np(1-p)

    so (1-p)=5.48/7.6 etc...

    CB
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  3. #3
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    So as the question is put chances of having a work accident is on a weekday is .2 and weekend is .3

    A is random variable representing no. of accidents in february

    mean of A is 7.6
    variance of A is 5.48

    for P(<=28)= 1-P(>=27) = 1-Bin(27,?,?.....

    Am i on the right path here?
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  4. #4
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    Quote Originally Posted by davidrocastle View Post
    So as the question is put chances of having a work accident is on a weekday is .2 and weekend is .3

    A is random variable representing no. of accidents in february

    mean of A is 7.6
    variance of A is 5.48

    for P(<=28)= 1-P(>=27) = 1-Bin(27,?,?.....

    Am i on the right path here?
    More or less but first work out the valuse of p and N.

    However you said earlier that you want p(A>=28)=1-p(A<=27).

    Also please calculate N, then think again about what the question is asking. Also check for typos.

    CB
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  5. #5
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    Sorry again i am a bit lost,

    what i was looking for is write an expression for probability that A>= 28

    How do i calculate N?

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