Dear R users,

I came up to a problem dealing with percentiles in R.

>From my previous questions: I do have a big data.frame, with lots of
columns and rows. The following command enables me to calculate means for
all data frame.

dat1$newID<-rep(1:(nrow(dat1)/12),each=12) #if nrow(dat1)/12 is integer

dat2<-with(dat1,aggregate(cbind(dat1[,1:71]),by=list(newID),mean))

What I need is to calculate percentiles for each group (there are 12 values
in a group). I tried the following:

duomenai<-with(dat1,aggregate(cbind(dat1[,1:71]),by=list(newID),quantiles,0.1,type=4))


First, is the following syntax is right?
Secondly, I tried to calculate percentiles using OpenOffice and there is
disagreement between values. If I do calculation for some number row, than
R and OpenOffice numbers coincide, but for a data.frame it seams that
something goes wrong.

Any thoughts will be appreciated.

-- 
Simonas Kecorius
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