Determining Bias of MLE of k in Poisson RP

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Discussion Overview

The discussion revolves around the maximum likelihood estimation (MLE) of the parameter k in a Poisson random process. Participants explore the properties of the MLE, particularly its bias, and the concept of sufficient statistics in relation to estimating k. The conversation includes theoretical considerations and questions about the nature of k as a variable.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant proposes that the MLE of k, denoted as k^ML, is given by the formula k^ML = [1 / (n*tau)] sigma (xi) and seeks to determine if it is biased.
  • Another participant states that k^ML is unbiased if the expected value E[k^ML] equals k, otherwise it is biased, hinting at the distribution properties of the Poisson random variable.
  • A participant expresses a desire to rewrite the problem using LaTeX and seeks clarification on whether N, the number of events, is a sufficient statistic or if actual event times are necessary for modeling.
  • There is a question raised about whether k is a random variable or a deterministic parameter, with one participant asserting that k is an unknown nonrandom variable, thus deterministic.
  • Clarification is sought regarding the notation used for N and n, with one participant noting a potential confusion in terminology.
  • A suggestion is made to study the concept of sufficient statistics to better understand the problem at hand.

Areas of Agreement / Disagreement

Participants express differing views on the nature of k, with some asserting it is deterministic while others question this characterization. The discussion on whether N is a sufficient statistic remains unresolved, with participants seeking further clarification.

Contextual Notes

There are unresolved questions regarding the definitions of sufficient statistics and the notation used for the number of events versus sample size. The discussion also reflects uncertainty about the implications of k being a random variable versus a deterministic parameter.

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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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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.
 
Last edited:
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) = [tex]\frac{(k\tau)}{n!}[/tex] [tex]^{n}[/tex] e[tex]^{-k\tau}[/tex]

  • 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 [tex]N[/tex], 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!
 


Is k a R.V., or is it a deterministic (although unknown) parameter (i.e. constant)?
 


k is a is an unknown nonrandom variable.

Based on this...I would say that it is deterministic...
 


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?
 


YES - you are correct. unfortunately, the write up I have is written very poorly.
 


"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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