Hi, Try: dat1 <- structure(list(Site = c("Downstream", "Downstream", "Downstream", "Downstream", "Downstream", "Downstream", "Downstream", "Downstream", "Downstream", "Midstream", "Midstream", "Midstream", "Midstream", "Midstream", "Upstream", "Upstream", "Upstream", "Upstream", "Upstream", "Upstream", "Upstream", "Upstream", "Upstream", "Upstream", "Upstream", "Upstream", "Upstream", "Upstream"), Intersex = c("no", "no", "no", "no", "yes", "no", "yes", "no", "no", "yes", "no", "no", "no", "no", "yes", "yes", "yes", "yes", "yes", "no", "no", "yes", "yes", "no", "yes", "no", "yes", "yes")), .Names = c("Site", "Intersex"), class = "data.frame", row.names = c("1", "2", "3", "4", "5", "6", "7", "8", "9", "10", "11", "12", "13", "14", "15", "16", "17", "18", "19", "20", "21", "22", "23", "24", "25", "26", "27", "28"))
res1 <- aggregate(Intersex~Site,data=dat1,function(x) (table(x)/length(x))*100) res1New <- do.call(`data.frame`,res1) #or library(plyr) res2 <- ddply(dat1,.(Site),summarize, Percent=(table(Intersex)/length(Intersex))*100) plot(Intersex.yes~as.numeric(Site),data=res1New,xaxt="n",xlab="Site",ylim=c(0,100),type="b") axis(1,at=as.numeric(res1New$Site),levels(res1New$Site)) A.K. Hi I have the following dataset: Site Intersex 1 Downstream no 2 Downstream no 3 Downstream no 4 Downstream no 5 Downstream yes 6 Downstream no 7 Downstream yes 8 Downstream no 9 Downstream no 10 Midstream yes 11 Midstream no 12 Midstream no 13 Midstream no 14 Midstream no 15 Upstream yes 16 Upstream yes 17 Upstream yes 18 Upstream yes 19 Upstream yes 20 Upstream no 21 Upstream no 22 Upstream yes 23 Upstream yes 24 Upstream no 25 Upstream yes 26 Upstream no 27 Upstream yes 28 Upstream yes I want to group the sites and calculate the percent of "yes" "no" for Intersex. Then I want to plot the prevalence of intersex (basically plot the percent of "yes" for each site. I'm stumped! Thanks ______________________________________________ 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.