Results 1 to 5 of 5

Thread: Probability Question Regarding defective chips

  1. #1
    Banned
    Joined
    Dec 2008
    From
    Mauritius
    Posts
    523

    Probability Question Regarding defective chips

    Question : If a box contains 75 good IC chips and 25 defective chips, and 12 chips are selected at random. Find
    i) the probability that no chip is defective
    ii) the probability that atleast one chip is defective
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Senior Member Danneedshelp's Avatar
    Joined
    Apr 2009
    Posts
    303
    Quote Originally Posted by zorro View Post
    Question : If a box contains 75 good IC chips and 25 defective chips, and 12 chips are selected at random. Find
    i) the probability that no chip is defective
    ii) the probability that atleast one chip is defective
    i) You want to probability non of the 12 randomly selected chips are defective. So, the 12 randomly selected chips must be selected from the 75 good chips.

    To me, the best solution is to use the hypergeometric distribution function

    <br />
\frac{\left(\begin{array}{cc}<br />
     25\\<br />
   0\\<br />
\end{array}\right)\left(\begin{array}{cc}<br />
     75\\<br />
   12\\<br />
\end{array}\right)}{\left(\begin{array}{cc}<br />
      100\\<br />
    12\\<br />
 \end{array}\right)}

    Here is some information on how to use the hypergeometric distribution: http://en.wikipedia.org/wiki/Hyperge...c_distribution.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Banned
    Joined
    Dec 2008
    From
    Mauritius
    Posts
    523

    Is this correct?

    Quote Originally Posted by Danneedshelp View Post
    i) You want to probability non of the 12 randomly selected chips are defective. So, the 12 randomly selected chips must be selected from the 75 good chips.

    To me, the best solution is to use the hypergeometric distribution function

    <br />
\frac{\left(\begin{array}{cc}<br />
     25\\<br />
   0\\<br />
\end{array}\right)\left(\begin{array}{cc}<br />
     75\\<br />
   12\\<br />
\end{array}\right)}{\left(\begin{array}{cc}<br />
      100\\<br />
    12\\<br />
 \end{array}\right)}

    Here is some information on how to use the hypergeometric distribution: Hypergeometric distribution - Wikipedia, the free encyclopedia.
    Probability of no chips being defective is P(A)
    <br />
P(A) = <br />
\frac{\left(\begin{array}{cc}<br />
     25\\<br />
   0\\<br />
\end{array}\right)\left(\begin{array}{cc}<br />
     75\\<br />
   12\\<br />
\end{array}\right)}{\left(\begin{array}{cc}<br />
      100\\<br />
    12\\<br />
 \end{array}\right)} = 0.025 .................Is this correct???


    ii) Probability of at least 1 chip being defective

    P(B \ge 1) = 1 - P(A).............am i correct?
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Master Of Puppets
    pickslides's Avatar
    Joined
    Sep 2008
    From
    Melbourne
    Posts
    5,237
    Thanks
    33
    Quote Originally Posted by zorro View Post

    P(B \ge 1) = 1 - P(A).............am i correct?
    Yep
    Follow Math Help Forum on Facebook and Google+

  5. #5
    Banned
    Joined
    Dec 2008
    From
    Mauritius
    Posts
    523

    Thanks for ur answer

    Quote Originally Posted by pickslides View Post
    Yep

    Thanks for all ur support guys
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 4
    Last Post: Dec 1st 2011, 01:08 PM
  2. Replies: 2
    Last Post: Mar 18th 2011, 10:38 AM
  3. Probability urn and chips question
    Posted in the Advanced Statistics Forum
    Replies: 1
    Last Post: Feb 2nd 2010, 06:27 PM
  4. If the probability of a defective bolt is
    Posted in the Statistics Forum
    Replies: 1
    Last Post: Jan 1st 2010, 02:28 PM
  5. [SOLVED] Probability(defective)
    Posted in the Statistics Forum
    Replies: 2
    Last Post: Aug 12th 2009, 08:13 AM

Search tags for this page

Click on a term to search for related topics.

Search Tags


/mathhelpforum @mathhelpforum