Percentiles with R for a big data.frame
On 13-01-21 6:41 PM, Simonas Kecorius wrote:
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))
You didn't define quantiles, so that won't work. Assuming that's a typo, and you meant quantile...
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.
There are lots of different formulas for empirical quantiles. The ones available in R are described in the ?quantile help topic. What formula does OpenOffice use? Duncan Murdoch