Results 1 to 4 of 4

Math Help - Binomial in reverse?

  1. #1
    Newbie
    Joined
    Mar 2013
    From
    Australia
    Posts
    3

    Binomial in reverse?

    Hi,

    I essentially want to calculate the minimum population size required (number of trials) in order to have say, a 99% chance of achieving 1 success.

    If P(y)= (nCy) py qn-y , P(y) in this case is equal to 0.99, y is equal to 1, and p and q are known. So I guess I need to solve for n, when n is not equal to y. Is this easily solveable?

    Cheers,
    Chips
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member
    Joined
    Oct 2012
    From
    Ireland
    Posts
    591
    Thanks
    159

    Re: Binomial in reverse?

    Remember nCy= n when y=1

    You will get a non algebraic equation for n which cannot be solved using normal methods. You may have to use an iterative method such as Newton's method - Wikipedia, the free encyclopedia to find n
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Newbie
    Joined
    Mar 2013
    From
    Australia
    Posts
    3

    Re: Binomial in reverse?

    Thanks Shakarri - I will look into solving this using some form of iteration. Of course, if anyone has any experience solving equations iteratively I would appreciate some tips on where to start, as I've never done this sort of thing before.
    Follow Math Help Forum on Facebook and Google+

  4. #4
    Super Member
    Joined
    Jul 2012
    From
    INDIA
    Posts
    829
    Thanks
    209

    Re: Binomial in reverse?

    Shakarri & WChips Note that nC1 = nC(n-1) = n
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. How to reverse log
    Posted in the New Users Forum
    Replies: 1
    Last Post: June 30th 2012, 03:38 AM
  2. normalizing reverse value of 0
    Posted in the Advanced Math Topics Forum
    Replies: 2
    Last Post: May 22nd 2010, 03:13 AM
  3. Goertzel Reverse
    Posted in the Calculus Forum
    Replies: 1
    Last Post: November 25th 2009, 05:46 PM
  4. Reverse Derivatives?
    Posted in the Calculus Forum
    Replies: 0
    Last Post: February 5th 2009, 08:16 PM
  5. reverse
    Posted in the Discrete Math Forum
    Replies: 1
    Last Post: August 3rd 2007, 06:33 AM

Search Tags


/mathhelpforum @mathhelpforum