Hello, Dora!
You wrote on Sun, 4 Feb 2007 08:52:38 -0600:

DS I am having trouble getting Excel to compute probabilities
DS as other than 0 or 1, though when I do examples on the web
DS that involve very small numbers I get teh correct answers
DS with no trouble.

DS Are poisson probabilities intended for this use? Or are
DS they only applicable for small numbers of discrete events,
DS like the liklihood that 4 cars will run a traffic light in
DS a day?

DS What would be the appropriate statistic for the probability
DS of meeting a goal of 700,000 discrete events in a month, or
DS a few million in a year?

Technically, I think Poisson statistics are correct but, for
such large numbers of events, normal statistics should produce
similar probabilities.

James Silverton
Potomac, Maryland

E-mail, with obvious alterations:
not.jim.silverton.at.comcast.not