Results 1 to 3 of 3

Math Help - Probability Teaser! Binomial dist or what?

  1. #1
    Newbie
    Joined
    Oct 2008
    Posts
    11

    Probability Teaser! Binomial dist or what?

    Problem: A material is known for 20% breakage under stress. Five different samples of such materials are tested.
    A. What is the probability that the third sample resists the stress?
    B. What is the probability that the third and fourth samples resist the stress?

    I don't know how to approach this question. I see that 1 material are damaged for every 5 tested, and I was thinking of using the binomial distribution for it. But I don't think I can, because I believe that distribution involves multiple. Can someone give me some direction to go with this?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Flow Master
    mr fantastic's Avatar
    Joined
    Dec 2007
    From
    Zeitgeist
    Posts
    16,948
    Thanks
    5
    Quote Originally Posted by isuckatprobability View Post
    Problem: A material is known for 20% breakage under stress. Five different samples of such materials are tested.
    A. What is the probability that the third sample resists the stress?

    Mr F says: 4/5

    B. What is the probability that the third and fourth samples resist the stress?

    Mr F says: (4/5)^2

    I don't know how to approach this question. I see that 1 material are damaged for every 5 tested, and I was thinking of using the binomial distribution for it. But I don't think I can, because I believe that distribution involves multiple. Can someone give me some direction to go with this?
    Here's a question to help you understand the answers:

    A coin is tossed 5 times.

    A. What's the probability that it comes up heads on the third toss?

    B. What's the probability that it comes up heads on the third and fourth toss?
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Oct 2008
    Posts
    11
    thankyou. That does make sense. So simple, I don't believe!
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Normal approx to the binomial dist. questions
    Posted in the Advanced Statistics Forum
    Replies: 1
    Last Post: February 1st 2010, 07:44 PM
  2. Two Ind. Poissons, prove conditional dist of Y1 is binomial
    Posted in the Advanced Statistics Forum
    Replies: 1
    Last Post: December 14th 2009, 09:16 PM
  3. Disease carrier problem with binomial dist.
    Posted in the Advanced Statistics Forum
    Replies: 1
    Last Post: October 9th 2009, 10:49 PM
  4. Cramer-Rao lower bound for Binomial dist
    Posted in the Advanced Statistics Forum
    Replies: 5
    Last Post: August 9th 2009, 08:24 AM
  5. Probability Teaser Question
    Posted in the Statistics Forum
    Replies: 1
    Last Post: October 15th 2008, 01:50 AM

Search Tags


/mathhelpforum @mathhelpforum