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The dispersion (standard deviation) of the estimator of neutron flux number

  1. Dec 12, 2012 #1
    Hello people, I think the problem what I have is well known in experimental physics. Hope, somebody can helps me, thanks in advance. Here is:

    There is a source of neutrons with a flux of λ neutrons per minute, which you do not know and want to estimate. You open the detector for one minute and it counts N neutrons. The maximum likelihood estimator for λ would be N.
    Find the dispersion (or standard deviation) of this estimator. What will it be for the limiting case N=0?

    Looks like Poisson distribution, where λ isn't known.
     
  2. jcsd
  3. Dec 12, 2012 #2

    DrDu

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    Yes, exactly. What is the standard deviation in terms of lambda for a Poisson distribution?
     
  4. Dec 12, 2012 #3
    Standard deviation in terms of lambda is square root from lambda, but my event is different I think, have you any idea?
     
  5. Dec 12, 2012 #4

    DrDu

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    I think this is the best you can get with just one measurement. To estimate an empirical variance would require at least two measurements.
     
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