It appears you posted in HTML and what we get is an almost useles set of data. It is much better to supply it using dput() (and always post to the list in plain text not HTML.
See https://github.com/hadley/devtools/wiki/Reproducibility of http://stackoverflow.com/questions/5963269/how-to-make-a-great-r-reproducible-example for some helpful hints on how to post to the R-Help list/ John Kane Kingston ON Canada > -----Original Message----- > From: sam_l_cruicksh...@hotmail.com > Sent: Tue, 19 Aug 2014 19:09:13 +0100 > To: r-help@r-project.org > Subject: [R] Negative values on output > > > > > > > Good afternoon, > I am completed a linear regression model which I personally am happy with > the output and residual charts (although they are a bit bunched). I have > been using visreg() to visualise my data, and although I have logged the > dependent variable (as it is cost data), on one of the graphical outputs > I am getting negative fitted values for one of the Continents. Attached > is the data used, below is the code for the model and graph. If anyone > has any ideas I would hugely appreciate it, I tried a glm with log link > too and this didn't help. > LM22 <- lm(logTotal ~ logArea + Continent + factor(Method1) + Popdens, > data=dummy) > Output Residuals: Min 1Q Median 3Q Max -1.22742 > -0.31675 -0.00909 0.28885 1.20224 > Coefficients: Estimate Std. Error t value Pr(>|t|) > (Intercept) -1.40972 0.77661 -1.815 0.081506 . logArea > 0.03811 0.04041 0.943 0.354619 ContinentAsia 3.51165 > 0.80009 4.389 0.000182 ***ContinentAustralasia 3.48549 0.97433 > 3.577 0.001454 ** ContinentEurope 2.44829 0.82369 2.972 > 0.006452 ** ContinentGlobal 2.37910 1.00668 2.363 0.026197 * > ContinentNorth America 2.27953 0.62960 3.621 0.001303 ** > ContinentSouth America 3.60997 0.77627 4.650 9.22e-05 > ***factor(Method1)2 1.11259 0.38386 2.898 0.007696 ** > factor(Method1)3 0.82519 0.47470 1.738 0.094459 . > factor(Method1)4 -0.06737 0.67341 -0.100 0.921104 Popdens > -0.14261 0.31675 -0.450 0.656435 ---Signif. codes: 0 *** 0.001 ** > 0.01 * 0.05 . 0.1 1 > Residual standard error: 0.6151 on 25 degrees of freedom (12 > observations deleted due to missingness)Multiple R-squared: 0.6998, > Adjusted R-squared: 0.5677 F-statistic: 5.297 on 11 and 25 DF, p-value: > 0.0002714 > visreg(LM22) gives me a graph with "Africa" being within the realm of > negative "Total" which is impossible. If you tell me how can provide > the data and graphs, but the email was kicked back with them in. > [[alternative HTML version deleted]] > > ______________________________________________ > 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. ____________________________________________________________ FREE ONLINE PHOTOSHARING - Share your photos online with your friends and family! Visit http://www.inbox.com/photosharing to find out more! ______________________________________________ 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.
