Results 1 to 4 of 4

Math Help - Probability question

  1. #1
    Junior Member
    Joined
    May 2009
    Posts
    31

    Probability question

    Hi,

    I made a survey where n people answered several questions; one of the questions was "What is your sign?"
    A person can be of one of the 12 signs of the zodiac.
    My question is: what is the probability of x people of n be of one specific sign?

    Kind regards,

    Kepler
    Follow Math Help Forum on Facebook and Google+

  2. #2
    MHF Contributor

    Joined
    Aug 2006
    Posts
    18,661
    Thanks
    1616
    Awards
    1

    Re: Probability question

    Quote Originally Posted by kepler View Post
    I made a survey where n people answered several questions; one of the questions was "What is your sign?"
    A person can be of one of the 12 signs of the zodiac.
    My question is: what is the probability of x people of n be of one specific sign?
    You must assume that this is binomial probability.
    \mathcal{P}(X=k)=\binom{N}{k}(p)^k(1-p)^{N-k} which means there are k happenings in N tries and p is the probability is occurs.

    So in your query, N is the number of people you survey and p=\tfrac{1}{12}~.
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Junior Member
    Joined
    May 2009
    Posts
    31

    Re: Probability question

    Quote Originally Posted by Plato View Post
    You must assume that this is binomial probability.
    \mathcal{P}(X=k)=\binom{N}{k}(p)^k(1-p)^{N-k} which means there are k happenings in N tries and p is the probability is occurs.

    So in your query, N is the number of people you survey and p=\tfrac{1}{12}~.
    Hi,

    So, it's:

    k!/(N!*(N-k)!)*(p^k)*((1-p)^(N-k))

    ?

    Kind regards,

    Kepler
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Junior Member
    Joined
    May 2009
    Posts
    31

    Re: Probability question

    Sorry...I mean:

    N!/(k!*(N-k)!)*(p^k)*((1-p)^(N-k))

    Kepler
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Replies: 1
    Last Post: May 6th 2013, 10:29 AM
  2. Replies: 0
    Last Post: May 5th 2013, 07:32 PM
  3. Replies: 5
    Last Post: February 10th 2013, 02:11 PM
  4. Probability question involving (A given B type question )
    Posted in the Advanced Statistics Forum
    Replies: 0
    Last Post: November 9th 2009, 09:08 AM
  5. A probability question and an Expectations question
    Posted in the Advanced Statistics Forum
    Replies: 1
    Last Post: January 29th 2006, 06:13 PM

Search Tags


/mathhelpforum @mathhelpforum