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Re: Geiger, not binomial ?



I don't understand. If a is the Poisson mean and N_n the no
of occurrences of n counts, then the successive ratios
N_n/N_(n+1) = (n+1)/a.
Kowalski's data are consistent with this, at least to n=6, with
an a of about 2.2. Since a is small, Poisson "skews" the distribution
toward a small number of counts. I see no reason to "count for a longer
time". The data are sufficient to determine a count rate.
Regards,
Jack

Adam was by constitution and proclivity a scientist; I was the same, and
we loved to call ourselves by that great name...Our first memorable
scientific discovery was the law that water and like fluids run downhill,
not up.
Mark Twain, <Extract from Eve's Autobiography>

On Thu, 23 Mar 2000, Michael Edmiston wrote:

I agree with Leigh. The distribution you want is the Poisson distribution.
And I also agree with Leigh that you need to count for a longer time.

To further explain the second point, note that your data, as taken, appear
skewed toward the low counts. You had very high incidence of one count and
high incidence of no counts in 0.5 second. That means you would also expect
reasonably high incidence of one count and no count for a period of one
second, or a period of two seconds, etc. So your method of data acquisition
means you aren't seeing the "whole story." You have "sampled the
distribution" fairly well for the right side of the tail, but you have
insufficient sampling for the left side of the tail.


Michael D. Edmiston, Ph.D. Phone/voice-mail: 419-358-3270
Professor of Chemistry & Physics FAX: 419-358-3323
Chairman, Science Department E-Mail edmiston@bluffton.edu
Bluffton College
280 West College Avenue
Bluffton, OH 45817