Re: Is n a parameter of a binomial distribution?
- From: vontressms@xxxxxx
- Date: Tue, 30 Oct 2007 06:11:28 -0700
On Oct 26, 1:35 pm, hru...@xxxxxxxxxxxxxxxxxxxx (Herman Rubin) wrote:
In article <1193247073.540767.154...@xxxxxxxxxxxxxxxxxxxxxxxxxxxx>,
<vontres...@xxxxxx> wrote:
On Oct 24, 10:53 am, hru...@xxxxxxxxxxxxxxxxxxxx (Herman Rubin) wrote:
In article <1192797455.065283.3...@xxxxxxxxxxxxxxxxxxxxxxxxxxx>,Herman,
<vontres...@xxxxxx> wrote:
On Oct 18, 1:23 pm, Vinayak Rao <vinayak....@xxxxxxxxx> wrote:Anything which can be computed from a probability
distribution is a parameter, so n is a parameter.
There is considerable information on the estimation
of n if p is known, and also if p is unknown.
A set of such parameters can be called the parameters
of a family of distributions if their values determine
the distribution. Usually, n and p are the parameters.
The binomial distribution belongs to the exponential
family with respect to p, but not with respect to n.
One gets a rather interesting estimation problem if
the parameters used are h = 1/n and np. In this case,
one gets the binomial distribution if 1/h is a positive
integer, Poisson if h = 0, and negative binomial if h < 0.
I will agree with you that anything that anything which can be
computed from a probability distribution is a parameter, so n is a
parameter if it has a probability distribution.
Any parameter of an distribution is function of that
distribution, and that is all. For a binomial
ditribution, the usual stated parameters are n and p,
but others can be used. For a given distribution,
there is nothing random about the distribution.
There is also the inference problem about parameters.
It may be that n is by far the more important parameter
than p. For example, suppose that one wants to test
whether p=.49 or p=.51. Suppose that if p=.49, items
come regularly once a second, and if p=.51, regularly
once an hour. Instead of fixing n, I suggest we fix
the time and go by how many have been seen.
--
This address is for information only. I do not claim that these views
are those of the Statistics Department or of Purdue University.
Herman Rubin, Department of Statistics, Purdue University
hru...@xxxxxxxxxxxxxxx Phone: (765)494-6054 FAX: (765)494-0558- Hide quoted text -
- Show quoted text -
Herman,
That is an interesting problem that I've never had to work with
before. It's pretty clear that you can get an MLE for N using x and a
prespecified p. How would you select p from your two choices?
Mark
.
- References:
- Is n a parameter of a binomial distribution?
- From: Vinayak Rao
- Re: Is n a parameter of a binomial distribution?
- From: vontressms
- Re: Is n a parameter of a binomial distribution?
- From: Herman Rubin
- Re: Is n a parameter of a binomial distribution?
- From: vontressms
- Re: Is n a parameter of a binomial distribution?
- From: Herman Rubin
- Is n a parameter of a binomial distribution?
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