Results 1 to 3 of 3

Math Help - 2 Binomial Probability Questions

  1. #1
    Newbie
    Joined
    Oct 2007
    Posts
    11

    2 Binomial Probability Questions

    The probability of an integrated circuit passing a quality test is 0.86. In a batch of 10 integrated circuits, find the probability that


    iii) at least 2 will fail
    iv) fewer than 2 will fail


    I know the forumula to use

    P(x) = NCr (a)^r (b)^r-1

    but when it gets "least" and "fewer" i start to get confused
    whats the easy to this i know its 1 - p(something) but not really sure

    Help please guys
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,617
    Thanks
    1581
    Awards
    1
    Quote Originally Posted by xibeleli View Post
    The probability of an integrated circuit passing a quality test is 0.86. In a batch of 10 integrated circuits, find the probability that
    iii) at least 2 will fail
    iv) fewer than 2 will fail
    The probability that none or one fails is \sum\limits_{k = 0}^1 {\binom{10}{k}\left( {.86} \right)^{10 - k} \left( {.14} \right)^k } .
    That answers (iv).
    Follow Math Help Forum on Facebook and Google+

  3. #3
    MHF Contributor matheagle's Avatar
    Joined
    Feb 2009
    Posts
    2,763
    Thanks
    5
    At least 2 means X is 2 or 3 or 4 or... 10. Here you want P(X\ge 2).

    Fewer than 2 means X is 0 or 1. Here you want P(X < 2)=P(X\le 1).

    Note that P(X\ge 2)+P(X\le 1)=1.

    And it's n-r, not r-1.
    Last edited by matheagle; June 7th 2009 at 06:47 AM.
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Binomial Probability Questions
    Posted in the Statistics Forum
    Replies: 1
    Last Post: February 6th 2011, 09:49 PM
  2. Binomial Theorum questions!
    Posted in the Algebra Forum
    Replies: 6
    Last Post: March 1st 2009, 05:26 AM
  3. Bernoulli, Binomial, and PMF questions
    Posted in the Advanced Statistics Forum
    Replies: 1
    Last Post: February 25th 2009, 11:02 AM
  4. Binomial Theorem - Questions
    Posted in the Math Topics Forum
    Replies: 5
    Last Post: November 27th 2008, 07:35 PM
  5. [SOLVED] Questions on binomial distribution probability
    Posted in the Statistics Forum
    Replies: 0
    Last Post: February 26th 2008, 08:36 PM

Search Tags


/mathhelpforum @mathhelpforum