Unformatted text preview: 18 POiSSOIl Distribution
I Suppose the number (if trials isn’t ﬁxed, but the instances or arrivals occur with some
frequency over ﬁxed time intervals. n 9% i The number of packages which are arriving a Wireless netwurk mule ,, The number of packages which are leaving a Wireless network node 0: Let X be the number of arrivals over a ﬁxed time interval, X N Poissonﬂ) a: c? - If” X! g ’ «sux
.' i M furr:071,2,._. o The mean is- given by E[X] : pa 2 A) the variance is given by VariX} = a ; o Example: Let X denote the number of rats caught in rat traps each night at a. local
restaurant. 011 Menage, there are 5 rats each mun-ling. ~ (a) What is the average number of rats caught? (b) “That is the standard deviation of the number of rats.” caught? Van“ [A135 CT: 5 mfg (a) What is the probabiiity no rats are caught? Kw) 30.0067Lt (d) What is the probability 5 rats are caught? ...
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- Fall '07