Your example seems strange because a line fits on the x-y scale; not on the log(x)-log(y) scale. Anyway, here is my example. You can build on it for more general data.
x <- exp(1:10) y <- exp(10:1 + rnorm(10)) logmod <- lm(log(y)~log(x)) logypred <- predict(logmod) plot(y~x) lines(exp(logypred)~x, col=2) plot(y~x, log="xy") lines(exp(logypred)~x, col=2) Chris -----Original Message----- From: Rui Barradas [mailto:ruipbarra...@sapo.pt] Sent: Friday, December 14, 2012 12:06 PM To: mrkooper Cc: r-help@r-project.org Subject: Re: [R] plotting log regression Hello, How can you expect to see the fit line if you are ploting x and y values, not their logarithms? And your definitions of x and y are wrong, they should use c(). x <- c(1,2,3,4,5) y <- c(6,7,8,9,10) plot(log(x), log(y)) fit <- lm(log(y) ~ log(x)) # Same as glm abline(fit) Please read R-intro, in the doc folder of your installation of R. Hope this helps, Rui Barradas Em 14-12-2012 13:58, mrkooper escreveu: > I want to plot the regression line of a log regression into a plot > with my normal, nonlog, data. > > for example > > x <- (1,2,3,4,5) > y <- (6,7,8,9,10) > > plot (x,y) > > I tried a log-regression by > > a <- glm (log(y) ~ log(x)) > > and then i tried to insert the answer to my graph, where the standard > values are shown: > abline (a, col="red") > > unfortunately it does not work.... > > > > > -- > View this message in context: > http://r.789695.n4.nabble.com/plotting-log-regression-tp4653087.html > Sent from the R help mailing list archive at Nabble.com. > > ______________________________________________ > 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. ********************************************************** Electronic Mail is not secure, may not be read every day, and should not be used for urgent or sensitive issues ______________________________________________ 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.
