🚀 go-pugleaf

*** For the line eater ***

Ok..I'm working on the following problem for one of my classes,
and can not find/figure out an "easy" way to solve it.

We are given a process that occurs 600 times/hour, and are to
calculate the following probabilities: (The first 2 are easy)

a) That there will be exactly 0 occurences in 3 minutes.
b) That there will be exactly 60 occurences in 3 minutes.

Now for the tough one:
c) If a switch board can handle 20 calls per minute,
that what is the probability that it will be overrun
in 3 minutes with a 600 call/hour poisson distribution?
(Ie: that there will be at least 1 minute with at least
21 calls?)

It seems to me that the way to solve it would be to
calculate SIGMA(P63(3)) (Ie..SUm of the probabilities
of 0-63 events) and subtract 1, giving the probability of
more than 63 events in 3 minutes (which means that we had*
to have 1 minute with more than 21, yes?) However,
*summing* that damn thing is no fun! Especially 63 cases!

By the bye, in case you forget
Pn(t) = [(rt)^n/n!] * e^(-rt)  where r = rate and t = time...n
is the number of occurances exactly*.

Thanks!



-- 
Steven J. McDowall	
Dayton-Hudson Dept. Store. Co.		UUCP: ihnp4!rosevax!dayton!sjm
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