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One lined question on probability?

  1. Feb 28, 2010 #1

    rock.freak667

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    One lined question on probability??

    1. The problem statement, all variables and given/known data
    A worker's record shows 60% of his projects are completed on time. If this performance prevails, write the distribution of X=the number of jobs completed in the next 6 jobs. Find the mean and variance of X


    2. Relevant equations



    3. The attempt at a solution

    I think that from x=1-6, P(X=x)= 0.6 ? I mean that was all I was given, there is no reason to think otherwise. Is there? Assuming I am correct, I can easily find the mean and the variance.
     
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  3. Feb 28, 2010 #2

    CompuChip

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    Re: One lined question on probability??

    Note that all probabilities should sum to 1...

    Does the word "binomial distribution" mean anything to you?
     
  4. Feb 28, 2010 #3

    rock.freak667

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    Re: One lined question on probability??

    ahhhh...I was so caught up in trying to make it uniform distribution :redface:

    So basically, the distribution is just X~Bin(6,0.6), except I need to write out the numbers and not just the pdf.
     
  5. Feb 28, 2010 #4

    CompuChip

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    Re: One lined question on probability??

    Yes, although it would be nice if you showed why it is binomial. I.e., that it satisfies the properties that a binomial experiment has.
     
  6. Feb 28, 2010 #5

    rock.freak667

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    Re: One lined question on probability??

    The workers 6 projects are independent and the worker can have 0-6 (k) successes (with each success being a constant)

    So X~Bin(n,p) = nCkpk(1-p)n-k
     
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