Results 1 to 3 of 3

Math Help - Bi-nomial distribution - shorter method?

  1. #1
    Super Member Quacky's Avatar
    Joined
    Nov 2009
    From
    Windsor, South-East England
    Posts
    901

    Bi-nomial distribution - shorter method?

    I've noticed this question in an exam paper:

    X is Bin(12,0.45)

    a) Find p(X\geq7)
    I could do this the long way which is to find p(x=0)+p(x=1)+p(x=2)+p(x=3)+p(x=4)+p(x=5)+p(x=6) and then do one take away from this answer, but the question is two marks: surely there's a shorter method?

    Edit:woops. mucked up the title...
    Last edited by Quacky; April 26th 2010 at 01:00 PM.
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Super Member
    Joined
    Sep 2008
    Posts
    607
    Quote Originally Posted by Quacky View Post
    I've noticed this question in an exam paper:

    X is Bin(12,0.45)

    a) Find p(X\geq7)
    I could do this the long way which is to find p(x=0)+p(x=1)+p(x=2)+p(x=3)+p(x=4)+p(x=5)+p(x=6) and then do one take away from this answer, but the question is two marks: surely there's a shorter method?

    Edit:woops. mucked up the title...
    Surely, you can use the binomial probability tables? As the Tables give probabilities for  P(X\leq x) than,  p(X\geq7) =  1- P(X\leq6)

    n= 12,
    P = 0.45
    Follow Math Help Forum on Facebook and Google+

  3. #3
    Super Member Quacky's Avatar
    Joined
    Nov 2009
    From
    Windsor, South-East England
    Posts
    901
    Yeah, you're right! The thing is, I used the table in the textbook which doesn't have values for 12. I SHOULD have been using the formula booklet, which does
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Need help with binomial distribution using the nCr method.
    Posted in the Advanced Statistics Forum
    Replies: 2
    Last Post: October 1st 2010, 11:51 AM
  2. Replies: 1
    Last Post: October 19th 2009, 09:52 PM
  3. Length of Shorter Diagonal
    Posted in the Geometry Forum
    Replies: 4
    Last Post: September 9th 2009, 08:51 AM
  4. Simulating continuos RVs - Inverse Distribution Method
    Posted in the Advanced Statistics Forum
    Replies: 8
    Last Post: August 17th 2009, 02:23 AM
  5. Method of moment generating function normal distribution
    Posted in the Advanced Statistics Forum
    Replies: 1
    Last Post: November 25th 2008, 02:22 AM

Search Tags


/mathhelpforum @mathhelpforum