Yes, fair enough. I wasn't sure it was fitting the mode at all, but here is an example of what I see
> model <- betareg(ACT ~ ST+DOY, data = actDL_F) Warning messages: 1: In sqrt(diag(fisherinv)) : NaNs produced 2: In sqrt(diag(fisherinv)) : NaNs produced 3: In sqrt(W) : NaNs produced 4: In sqrt(W) : NaNs produced 5: In sqrt(1 + phihat) : NaNs produced Call: betareg(formula = ACT ~ ST + DOY, data = actDL_F) Coefficients: (Intercept) ST DOY phi 1.780e+07 -1.149e+09 2.225e+08 -4.090e+08 So I don't see a W listed, but the phi is going negative just as you suggested. So are the results wonky if phi is negative? Ben Bolker wrote: > > knussear <knussear <at> mac.com> writes: > >> >> >> Hi >> >> I'm trying to fit a model in betareg and I'm getting errors, but have no >> idea what they mean or how to solve them. Does anyone have experience >> with >> this? >> >> > model <- betareg(ACT ~ ST*SoilT, data = actDL_F) >> Warning messages: >> 1: In sqrt(W) : NaNs produced >> 2: In sqrt(W) : NaNs produced >> 3: In sqrt(1 + phihat) : NaNs produced >> >> data summaries don't give any na's or problems I can see >> >> > summary(actDL_F$ACT) >> Min. 1st Qu. Median Mean 3rd Qu. Max. >> 0.0006227 0.0505600 0.2163000 0.2643000 0.4084000 0.9994000 >> >> > summary(actDL_F$ST) >> Min. 1st Qu. Median Mean 3rd Qu. Max. >> 8.085 29.560 34.760 33.870 39.430 49.610 >> >> > summary(actDL_F$SoilT) >> Min. 1st Qu. Median Mean 3rd Qu. Max. >> 17.42 20.95 24.18 24.26 27.21 31.19 >> >> Thanks >> >> Ken > > Note that these results are from the contributed "betareg" > package, so if my answer doesn't do it for you, you could > contact the package authors (see help(package="betareg") ). > Also note that you haven't given us a reproducible example, > so there's no way we can say for sure. > > That said: it seems *likely* (take my word for it > at your own risk) that W (whatever it is) and phihat > (whatever it is) are not constrained to be positive, > so they might wander negative in the course of the > optimization. If this is not fatal to > the optimization process, then you can still arrive > at a reasonable solution where they are all positive. > There doesn't seem to be see any "trace" option in > betareg, so it will be a little harder to see what's > going on. > > It's not wonky data I would worry about, but wonky > results (which you haven't shown us). > > Ben Bolker > > ______________________________________________ > 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. > > -- View this message in context: http://www.nabble.com/need-help-with-errors-in-betareg-analysis-tp22000860p22017178.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.
