Greetings I've been using SLqPCR on data that contains some NA values and have discovered what I think is a bug in the geomMean method. if(any(x < 0)) stop("'x' contains negative value(s)") if(na.rm) x <- x[!is.na(x)] should be if(na.rm) x <- x[!is.na(x)] if(any(x < 0)) stop("'x' contains negative value(s)") or the any() method fails because the result is not TRUE/FALSE. Best Regards, Mike Michael Muratet, Ph.D. Senior Scientist HudsonAlpha Institute for Biotechnology mmuratet at hudsonalpha.org (256) 327-0473 (p) (256) 327-0966 (f) Room 4005 601 Genome Way Huntsville, Alabama 35806