[R] Poisson distribution help requested

Spencer Graves spencer.graves at pdf.com
Fri Jan 9 16:32:09 CET 2004

 > ppois(0:11, 2)
 [1] 0.1353353 0.4060058 0.6766764 0.8571235 0.9473470 0.9834364 0.9954662
 [8] 0.9989033 0.9997626 0.9999535 0.9999917 0.9999986

This is the cumulative distribution function of the Poisson with mean 2 
at the values 0 - 11. 

hope this helps.  spencer graves

Mark St.John wrote:

>Could somebody help me to understand the syntax of R's ppois function? I'm looking to calculate the cumulative probability density of an observed value (y) given the expected mean (mu) and the level of significance (alpha). I'm coming from using SAS to do this and don't recognize the descriptions of the arguments for ppois. The definitions of lambda and p as stated in the R manuals are foreign to me!
>Thanks, Mark
>R-help at stat.math.ethz.ch mailing list
>PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html

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