Thank you all (David, Michael, Giovanni) for your prompt response. First there was a typo error for the group mean it was 89.6 not 87.
For a small data set and few groupings I can use prob=c(0, .333, .66 ,1) to group in to three groups in this case. However, if I want to extend the number of groupings say 10 or 15 then do I have to figure it out the split(x, cut(x, quantile(x, prob=c(0, .333, .66 ,1)) Is there a short cut for that? Thanks On Tue, Apr 3, 2012 at 9:13 AM, R. Michael Weylandt < michael.weyla...@gmail.com> wrote: > Ignoring the fact your desired answers are wrong, I'd split the > separating part and the group means parts into three steps: > > i) quantile() can help you get the split points, > ii) findInterval() can assign each y to a group > iii) then ave() or tapply() will do group-wise means > > Something like: > > y <- c(36, 45, 46, 66, 78, 125, 193, 209, 242, 297) # You need a "c" here. > ave(y, findInterval(y, quantile(y, c(0.33, 0.66)))) > tapply(y, findInterval(y, quantile(y, c(0.33, 0.66))), mean) > > You could also use cut2 from the Hmisc package to combine findInterval > and quantile into a single step. > > Depending on your desired output. > > Hope that helps, > Michael > > On Tue, Apr 3, 2012 at 8:47 AM, Val <valkr...@gmail.com> wrote: > > Hi all, > > > > Assume that I have the following 10 data points. > > x=c( 46, 125 , 36 ,193, 209, 78, 66, 242 , 297 , 45) > > > > sort x and get the following > > y= (36 , 45 , 46, 66, 78, 125,193, 209, 242, 297) > > > > I want to group the sorted data point (y) into equal number of > > observation per group. In this case there will be three groups. The > first > > two groups will have three observation and the third will have four > > observations > > > > group 1 = 34, 45, 46 > > group 2 = 66, 78, 125 > > group 3 = 193, 209, 242,297 > > > > Finally I want to calculate the group mean > > > > group 1 = 42 > > group 2 = 87 > > group 3 = 234 > > > > Can anyone help me out? > > > > In SAS I used to do it using proc rank. > > > > thanks in advance > > > > Val > > > > [[alternative HTML version deleted]] > > > > ______________________________________________ > > R-help@r-project.org mailing list > > https://stat.ethz.ch/mailman/listinfo/r-help > > PLEASE do read the posting guide > http://www.R-project.org/posting-guide.html > > and provide commented, minimal, self-contained, reproducible code. > [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
