Hello, I really need help, I am completely new in using R and many things were possible to figure out but not my last problem. I created a dotchart with the dotchart2 command. On the y axis are my 16 groups and plotted is the mean of the data from each group. And now I want to add the SD for every mean data point. Sure, I can calculate the SD (with removing the NAs that are present in my data by na.rm=TRUE) but I don?t know how to combine the graph with the SD. I found the arrows function but it looks weird when I try to plot: arrows(x0=m,y0=c(1:16),y1=c(1:16)-1,x1=m+1 length=0) -> "m" is the calculated mean of my data with removed NAs and 167 because of the 16 treatments Has somebody please, please any (easy) suggestion how to do it? I hope to get some help. Thank you very much for reading this. -- View this message in context: http://r.789695.n4.nabble.com/help-with-adding-SD-to-graph-tp4673558.html Sent from the R help mailing list archive at Nabble.com.