1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Homework Help: P(X=i) from given PGF

  1. Dec 11, 2005 #1
    Hi people, I was wondering if anyone could give me a hint with this problem.
    A RV X has PGF Gx(s)= (4-s)/3(4-3s)

    I need to get the P(X=i) from here. I know i can manipulate the above to get the sum to infinity of a geometric series, but i end up with the term
    (4-s) still in the P(X=i) which i dont think can be right. Anybody got any hints on how to rearrange the above so as to eliminate the s in the numerator so I can obtain P(X=i)? Thanks a lot, Jack
  2. jcsd
  3. Dec 11, 2005 #2

    matt grime

    User Avatar
    Science Advisor
    Homework Helper

    multiply out the (4-s) and the infinte series.
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook