Results 1 to 2 of 2

Math Help - Compound experiment with NNIV

  1. #1
    Super Member
    Joined
    Mar 2006
    Posts
    705
    Thanks
    2

    Compound experiment with NNIV

    Let X be a non-negative integer valued random variable. Observe X items and mark each of the X items independently with probability s where 0<s<1. What is the probability that all X items are marked?

    Solution so far:

    On the surface it looks like Pr[all \ items \ marked ] = s^X , but I know there is no way this can be this easy... What am I doing wrong?
    Follow Math Help Forum on Facebook and Google+

  2. #2
    Moo
    Moo is offline
    A Cute Angle Moo's Avatar
    Joined
    Mar 2008
    From
    P(I'm here)=1/3, P(I'm there)=t+1/3
    Posts
    5,618
    Thanks
    6

    Re: Compound experiment with NNIV

    Hello,

    Your mistake is that you're not considering X as a random variable.

    What you can compute is P(all items marked|X=x)=s^x
    But if you want the probability, not the conditional one, just remember that E[X]=E[E[X|Y]] (and that a probability is an expectation).
    Thus P(all items marked)=E[P(all items marked|X)]=E[s^X]
    Follow Math Help Forum on Facebook and Google+

Similar Math Help Forum Discussions

  1. Die experiment
    Posted in the Statistics Forum
    Replies: 7
    Last Post: October 17th 2011, 02:30 PM
  2. Help with experiment...
    Posted in the Math Topics Forum
    Replies: 3
    Last Post: March 6th 2010, 06:35 AM
  3. probability on experiment
    Posted in the Statistics Forum
    Replies: 1
    Last Post: January 19th 2009, 12:08 AM
  4. Experiment
    Posted in the Advanced Statistics Forum
    Replies: 1
    Last Post: April 29th 2008, 06:33 PM

Search Tags


/mathhelpforum @mathhelpforum