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Old Jun7-09, 08:08 PM                  #1
ACM_acm

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Poisson RP: MLE of "k"

P(n,tau) = [ [ (k*tau)^n ] / n! ] * exp(-k*tau)

Parameter k is the process of an unknown non random variable that I want to estimate.

I have determined that k^ML = [1 / (n*tau) ] sigma (xi)

I believe this is correct...

How do I determine if K^ML is biased?
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Old Jun7-09, 10:32 PM       Last edited by EnumaElish; Jun8-09 at 01:22 AM..            #2
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Re: Poisson RP: MLE of "k"

k^ML is unbiased if E[k^ML] = k, otherwise it is biased.

Hint: since each x is distributed Poisson with mean = k, ∑x is distributed Poisson with mean = Nk, where N is the number of x's.
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Old Jun8-09, 07:30 AM                  #3
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Poisson Random Process, Sufficient Statistic

OK - I think I understand you...I would like to rewrite the problem using the LATEX symbology...This is my first time to this website and I would like to learn this program....

My problem is stated as follows...
  • Stationary Poisson Random Process
  • The probability of n events in an interval of time tau is

P(n,tau) = LaTeX Code: \\frac{(k\\tau)}{n!} LaTeX Code: ^{n} eLaTeX Code: ^{-k\\tau}
  • parameter k is an unknown RV that I want to estiamte
  • I will observe x(t) over an interval (0,T)

My questions are as follows...

(1) is LaTeX Code: N , the number of events that occur in the interval (),T), a sufficient statistic, or is it necessary to record the actual event times?

I am not sure what this question is looking for....how can I model this? or think of it? Once I get this part, I will move on to the rest of the problem...

Thanks in advance!
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Old Jun8-09, 10:45 AM                  #4
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Re: Poisson RP: MLE of "k"

Is k a R.V., or is it a deterministic (although unknown) parameter (i.e. constant)?
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Old Jun8-09, 10:49 AM                  #5
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Re: Poisson RP: MLE of "k"

k is a is an unknown nonrandom variable.

Based on this....I would say that it is deterministic....
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Old Jun8-09, 10:51 AM                  #6
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Re: Poisson RP: MLE of "k"

In your later post you wrote N is the number of events. I had used N as the sample size (number of x's). Did you mean to write n instead?
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Old Jun8-09, 10:55 AM                  #7
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Re: Poisson RP: MLE of "k"

YES - you are correct. Unfortunatly, the write up I have is written very poorly.
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Old Jun9-09, 12:58 AM                  #8
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Re: Poisson RP: MLE of "k"

"I am not sure what this question is looking for....how can I model this? or think of it? Once I get this part, I will move on to the rest of the problem..."

You can start with studying the concept of Sufficient Statistic. See, for example, http://en.wikipedia.org/wiki/Sufficient_statistic
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