1. Not finding help here? Sign up for a free 30min 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!

Poisson distribution ?

  1. Mar 1, 2012 #1
    1. The problem statement, all variables and given/known data
    Telephone calls enter a college switchboard according to a Poisson process on the average of three calls every 4 minutes (i.e., at a rate of λ=0.75 per minute). Let W denote the waiting time in minutes until the second call. Compute P(W>1.5 minutes).


    2. Relevant equations



    3. The attempt at a solution

    I don't get it. No idea how to do it. I guess 1.5 means here that at the most 1 event can occur here.
     
  2. jcsd
  3. Mar 1, 2012 #2

    Ray Vickson

    User Avatar
    Science Advisor
    Homework Helper

    You DO know how to do it. Your guess is correct: do you see why?

    RGV
     
  4. Mar 1, 2012 #3
    No, I don't. The poisson distribution is not in this chapter. It's Weibull, Gompertz, extreme value, gamma, chi-square, and logonormal. I don't know which one of those it is.
     
  5. Mar 1, 2012 #4

    Ray Vickson

    User Avatar
    Science Advisor
    Homework Helper

    Well, it's related to the Gamma.

    However, let me ask you: what does the Poisson distribution represent? Never mind if it is not in that chapter; it is either in another chapter or else in another book or else in thousands of web pages. So, you have a Poisson distribution with m = 1.5*0.75 = 9/8 = 1.125; that would be the expected number of calls to occur in a 1.5 minute period. You can find the probability distribution of the number of calls in a 1.5-minute period by using the Poisson distribution formula for mean m. Now ask: if you need to wait > 1.5 min for the second call, how many have arrived before time 1.5? What is the probability of that?

    RGV
     
    Last edited: Mar 2, 2012
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Poisson distribution ?
  1. Poisson Distribution (Replies: 1)

  2. Poisson distribution (Replies: 11)

Loading...