Just have a look at ?quantile and the probs argument. tapply(x, l.c.1, quantile,probs=0.75)
Anyway, quantiles and quartiles are not the same. I guess you meant the 3rd quartile. > All - > > I have an example data frame > > x l.c.1 > 43.38812035 085 > 47.55710661 085 > 47.55710661 085 > 51.99211429 085 > 51.99211429 095 > 54.78449958 095 > 54.78449958 095 > 56.70201864 095 > 56.70201864 105 > 59.66361903 105 > 61.69573564 105 > 61.69573564 105 > 63.77469479 115 > 64.83191994 115 > 64.83191994 115 > 66.98222118 115 > 66.98222118 125 > 66.98222118 125 > 66.98222118 125 > 66.98222118 125 > > and I'd like to get the 3rd quantile by l.c.1 so I use > > tapply(x, l.c.1, quantile) > > and my output includes all quantiles (i.e., 0, 25%, 50%, 75%, 100%) > but I'm only interested in the 75% quantile. Is there an additional > statement or function I can use to get just the quantile that I want? > > Thanks for your help - > > SR > Steven H. Ranney > > ______________________________________________ > 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. > ______________________________________________ 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.