It's looks like you think that type=2 are the 'true' quantiles, but the default method in R is type=7 You might want to look at ?stats::quantile hth david freedman -- View this message in context: http://n4.nabble.com/Quartiles-and-Inter-Quartile-Range-tp1145817p1213199.html Sent from the R help mailing list archive at Nabble.com.