Dear R help, This seems to be a commonly asked question and I am able to run examples that have been proposed, but I can't seems to get this to work with my own data. Reproducible code is below. Thank you in advance for any help you can provide.
The main problem is that I can not get the confidence lines to plot correctly. The secondary problem is that predict is not able to find my object when I include a model object. ## THE DATA wt.data <- data.frame(code = factor(LETTERS[1:24]), area = c(60865,480,656792,92298,1200,1490,8202,4000,220,245,4000,390,325, 16,162911,20235,68800,3389,7,696,4050,1498,1214,99460), species = c(673,650,1353,1026,549,536,782,734,516,580,673,560,641,443,1105, 871,789,575,216,407,942,655,582,1018)) # TRANSFORM AND ADD TO DATAFRAME wt.data$logA <- log10(wt.data$area) wt.data$logS <- log10(wt.data$species) wt.mod <- lm(logS~logA, data = wt.data) # PLOT THE DATA with(wt.data,plot(logA,logS, ylim = c(2.3,3.2),xlim = c(0,6))) abline(wt.mod, lwd = 2) # create a prediction dataframe the same length as data pred.frame <- data.frame(a = seq(0,6, length.out = 24)) # error ' object "logA" not found' # I am not sure why object is not found, I assume this has to do with # the way I added the transformed variables to the dataframe pp <- predict(wt.mod, int = "p", newdata=pred.frame) # runs ok? pp <- predict(lm(wt.data$logS~wt.data$logA), int = "p", newdata=pred.frame) # lines are jagged?? # I am not sure how to get the lines to draw correctly here matlines(pred.frame$a,pp, lty=c(1,2,2),col="black") > sessionInfo() R version 2.8.1 (2008-12-22) i386-pc-mingw32 locale: LC_COLLATE=English_United States.1252;LC_CTYPE=English_United States.1252;LC_MONETARY=English_United States.1252;LC_NUMERIC=C;LC_TIME=English_United States.1252 attached base packages: [1] stats graphics grDevices utils datasets methods base loaded via a namespace (and not attached): [1] tools_2.8.1 Michael Denslow Graduate Student I.W. Carpenter Jr. Herbarium [BOON] Department of Biology Appalachian State University Boone, North Carolina U.S.A. -- AND -- Communications Manager Southeast Regional Network of Expertise and Collections sernec.org ______________________________________________ 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.