Thanks everyone for all you help. I have a good understanding of pois and it's variants now.
To clear up some discussion, I must apologize for being so sloppy as to list alpha as one of the parameters I would use in calculating Poisson PDFs in SAS. I include the value of alpha used to determine mu in my SAS programs as a reminder to myself, so I'd know where mu came from. Sorry for the red herring! So ppois(x:y, lambda=mu, lower.tail = F) was what I was after. Thanks again, Mark --- Peter Dalgaard <[EMAIL PROTECTED]> wrote: Martin Maechler <[EMAIL PROTECTED]> writes: > >>>>> "Spencer" == Spencer Graves <[EMAIL PROTECTED]> > >>>>> on Fri, 09 Jan 2004 07:32:09 -0800 writes: > > >> ppois(0:11, 2) > Spencer> [1] 0.1353353 0.4060058 0.6766764 0.8571235 > Spencer> 0.9473470 0.9834364 0.9954662 [8] 0.9989033 > Spencer> 0.9997626 0.9999535 0.9999917 0.9999986 > > Spencer> This is the cumulative distribution function of the > Spencer> Poisson with mean 2 at the values 0 - 11. > > Spencer> hope this helps. spencer graves > > and from Mark's "level of significance (alpha)", > I presume Mark really wants qpois() which computes quantiles, > i.e., the *inverse* of ppois(). But SAS doesn't seem to do Poisson quantiles.... However, data; input x; y = poisson(1,x); datalines; 0 1 2 3 4 ; proc print; run; Produces Obs x y 1 0 0.36788 2 1 0.73576 3 2 0.91970 4 3 0.98101 5 4 0.99634 which is similar to > ppois(0:4,1) [1] 0.3678794 0.7357589 0.9196986 0.9810118 0.9963402 -- O__ ---- Peter Dalgaard Blegdamsvej 3 c/ /'_ --- Dept. of Biostatistics 2200 Cph. N (*) \(*) -- University of Copenhagen Denmark Ph: (+45) 35327918 ~~~~~~~~~~ - ([EMAIL PROTECTED]) FAX: (+45) 35327907 ______________________________________________ [EMAIL PROTECTED] mailing list https://www.stat.math.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide! http://www.R-project.org/posting-guide.html
