Thanks to Deepayan's suggestion, I was able to use boxplot.stats to specify type=6 to calculate quantiles by creating my own stats function as follows,
my.boxplot.stats<-function(y,subscripts,...)boxplot.stats(quantile(y,type=6),...) And then call bwplot(Result~Group,data=d2,stats=my.boxplot.stats) However the whisker lines are missing when there are outliers. Also not all the outliers are drawn but only the maximum or the minimum. I appreciate any comment from the group. Thanks. Jun On Tue, Jul 21, 2009 at 10:20 AM, Deepayan Sarkar <deepayan.sar...@gmail.com > wrote: > On Tue, Jul 21, 2009 at 7:47 AM, Jun Shen<jun.shen...@gmail.com> wrote: > > Uwe, > > > > Thank you for your reply. I am still not very clear about the meanings > of > > the arguments in the stats function. To make it clearer, quantile() > uses > > type=7 as default method. I believe this is the method bwplot() uses to > > calculate the quantiles. I want to use type=6 method for bwplot(). How do > I > > achieve that? Thanks again. > > Maybe this will be clearer: bwplot() uses the boxplot.stats() function > to compute the "quantiles" used, which in turn uses fivenum(), which > has its own quantile calculation (and does not explicitly use > quantile()). There is no easy way to allow for type=6 etc. here. > > bwplot() allows you to replace boxplot.stats() and provide your own > alternative. So what you need to do is: > > (1) write a function, say, 'my.boxpot.stats', that takes the same > arguments as boxplot.stats() and returns a similar result, but using > your preferred calculation for the quantiles. There are many ways to > do this. > > (2) plug in this function into the bwplot() call; e.g. bwplot(..., > stats = my.boxplot.stats) > > -Deepayan > > > > > > Jun > > > > 2009/7/21 Uwe Ligges <lig...@statistik.tu-dortmund.de> > > > >> > >> > >> Jun Shen wrote: > >> > >>> Hi, everyone, > >>> > >>> Since quantile calculation has nine different methods in R, I wonder > how I > >>> specify a method when calling the bwplot() in lattice. I couldn't find > any > >>> information in the documentation. Thanks. > >>> > >>> > >> > >> bwplot() uses the panel function panel.bwplot() which allows to specify > a > >> function that calculates the statistics in its argument stats that > defaults > >> to boxplot.stats(). Hence you can change that function. > >> > >> Example with some fixed values: > >> > >> bwplot( ~ 1:10, > >> stats = function(x, ...) > >> return(list(stats=1:5, n=10, conf=1, 10, out=integer(0))) > >> ) > >> > >> > >> Uwe Ligges > >> > > > > [[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. > > > -- Jun Shen PhD PK/PD Scientist BioPharma Services Millipore Corporation 15 Research Park Dr. St Charles, MO 63304 Direct: 636-720-1589 [[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.
