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Homework Help: Possson Probablilty

  1. Oct 22, 2011 #1
    Cars pass at randoms times at an average rate of one a minute. The chance of a car stopping to give you a lift is one percent. What is the probability you will have got a lift within one hour?

    This has pretty much stumped me. I know λ=60 as expecting 60 cars an hour for the poisson distribution but there's a binomial aspect to this as well because of each car either giving you a lift or not giving you a lift
     
  2. jcsd
  3. Oct 22, 2011 #2

    vela

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    It's probably easiest to calculate the probability you don't get a ride and then subtract that from 1.
     
  4. Oct 23, 2011 #3
    I agree! But how?
     
  5. Oct 23, 2011 #4

    vela

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    What's the probability that exactly n cars pass in an hour?
     
  6. Oct 23, 2011 #5

    Ray Vickson

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    If N is the number of cars passing in time t, the event E = {no ride in time t} consists of {N=0} or {N=1 & no ride} or {N=2 & no ride} or .... . Are you familiar with the exponential series? If not, see http://en.wikipedia.org/wiki/Exponential_function .

    RGV
     
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