Results 1 to 8 of 8

Math Help - Probability

  1. #1
    Junior Member
    Joined
    Jan 2007
    Posts
    36

    Angry Probability

    if 20% of the bolts produced by a machine are defective, determine the probability that out of 4 bolts chosen at random,

    a 1 defective

    b none defective

    c at most 2 bolts will be defective

    think i have it just not sure?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    GAMMA Mathematics
    colby2152's Avatar
    Joined
    Nov 2007
    From
    Alexandria, VA
    Posts
    1,172
    Awards
    1
    Quote Originally Posted by question View Post
    if 20% of the bolts produced by a machine are defective, determine the probability that out of 4 bolts chosen at random,

    a 1 defective

    b none defective

    c at most 2 bolts will be defective

    think i have it just not sure?
    A) P(1) = .2^1(.8)^3 4\choose1 \Rightarrow .4096
    Follow Math Help Forum on Facebook and Google+

  3. #3
    is up to his old tricks again! Jhevon's Avatar
    Joined
    Feb 2007
    From
    New York, USA
    Posts
    11,663
    Thanks
    3
    this is a binomial distribution problem. see if post #2 here helps
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Junior Member
    Joined
    Jan 2007
    Posts
    36
    Quote Originally Posted by colby2152 View Post
    A) P(1) = .2^1(.8)^3 4\choose1 \Rightarrow .4096


    could u possibly post the formula in its pure form with its components explained
    Follow Math Help Forum on Facebook and Google+

  5. #5
    is up to his old tricks again! Jhevon's Avatar
    Joined
    Feb 2007
    From
    New York, USA
    Posts
    11,663
    Thanks
    3
    Quote Originally Posted by question View Post
    could u possibly post the formula in its pure form with its components explained
    i did that in the post i directed you to
    Follow Math Help Forum on Facebook and Google+

  6. #6
    Junior Member
    Joined
    Jan 2007
    Posts
    36
    Quote Originally Posted by question View Post
    if 20% of the bolts produced by a machine are defective, determine the probability that out of 4 bolts chosen at random,

    a 1 defective

    b none defective

    c at most 2 bolts will be defective

    think i have it just not sure?
    for part c i have the following:

    (4c2).(0.2)^2.(0.8^2) = 0.1536

    this is the answer that we were supposed to arrive at, but just looking at the wording of the question im not sure if its correct.

    Can anyone verify???
    Follow Math Help Forum on Facebook and Google+

  7. #7
    is up to his old tricks again! Jhevon's Avatar
    Joined
    Feb 2007
    From
    New York, USA
    Posts
    11,663
    Thanks
    3
    Quote Originally Posted by question View Post
    for part c i have the following:

    (4c2).(0.2)^2.(0.8^2) = 0.1536

    this is the answer that we were supposed to arrive at, but just looking at the wording of the question im not sure if its correct.

    Can anyone verify???
    no. that is if EXACTLY two are defective. "at most two" means 2 or less. meaning 0 or 1 or 2 (or more easily, not(3 or 4))
    Follow Math Help Forum on Facebook and Google+

  8. #8
    GAMMA Mathematics
    colby2152's Avatar
    Joined
    Nov 2007
    From
    Alexandria, VA
    Posts
    1,172
    Awards
    1
    Quote Originally Posted by question View Post
    if 20% of the bolts produced by a machine are defective, determine the probability that out of 4 bolts chosen at random,

    a 1 defective

    b none defective

    c at most 2 bolts will be defective

    think i have it just not sure?
    BTW, the solution to c will start off like this:

    P(at most 2) = P(0) + P(1) + P(2) \Rightarrow 1 - P(3) - P(4)
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 10
    Last Post: January 21st 2011, 11:47 AM
  2. Replies: 0
    Last Post: December 6th 2010, 04:57 PM
  3. Replies: 3
    Last Post: May 29th 2010, 07:29 AM
  4. Replies: 1
    Last Post: February 18th 2010, 01:54 AM
  5. Replies: 3
    Last Post: December 15th 2009, 06:30 AM

Search Tags


/mathhelpforum @mathhelpforum