[R] Percentile function

Peter Dalgaard BSA p.dalgaard at biostat.ku.dk
Tue Oct 17 14:40:15 CEST 2000

Art Salwin <salwin at mitretek.org> writes:

> Is there an R function that inputs a value and a vector, and
> returns the percentile corresponding to the value?  
> Something like
> pvalue<-function(x,vector){mean(x>=vector)} 
> but with interpolation.

That's essentially what quantile() does. Be aware though that the
definition it uses is that of the sum polygon, with the smallest
observation at 0% and the largest at 100% and the value at observation
point i being (i-1)*100%/(N-1). This is not quite the definition you
have and often not what people expect...

   O__  ---- Peter Dalgaard             Blegdamsvej 3  
  c/ /'_ --- Dept. of Biostatistics     2200 Cph. N   
 (*) \(*) -- University of Copenhagen   Denmark      Ph: (+45) 35327918
~~~~~~~~~~ - (p.dalgaard at biostat.ku.dk)             FAX: (+45) 35327907
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