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Homework Help: Binomial Distribution

  1. Jan 23, 2012 #1
    1. The problem statement, all variables and given/known data
    http://puu.sh/epl6 [Broken]
    Answer
    http://puu.sh/eplm [Broken]


    2. Relevant equations



    3. The attempt at a solution
    No clue on how to attempt this problem. Any help would be appreciated, thanks!
     
    Last edited by a moderator: May 5, 2017
  2. jcsd
  3. Jan 24, 2012 #2

    Ray Vickson

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    Homework Helper

    (a) What is the formula for [itex] f(k) \equiv \Pr\{X = k|X \geq 2 \},[/itex] for k = 2, 3, ...,n? Then [itex] E(X | X \geq 2) = \sum_{k=2}^n k f(k), [/itex] and you ought to be able to get the cited formula from this.
    (b) What is the formula for σ in terms of n and p? Look at it carefully.

    RGV
     
    Last edited by a moderator: May 5, 2017
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