search for: tweedie

Hello all, I have count data with about 36% of observations being zeros. I found in some of the examples of the r-help mail archives that a tweedie family of distributions could be used to fit a model with random effects. Upon installing the tweedie package and attempting to fit the following model: lmer(SUS ~ 1 + (1| GRP),REML=FALSE,data=mydata,family=tweedie(var.power=1.55,link.power=0)) I get the following error: Error in famType(...

...urse. When I replace that line with tmp <- .Fortran( .NAME="pdf", <other parameters here>) ...the package then does not pass the checks. The library package builds OK with no errors or warnings, and then during "R CMD check" the examples give this error: out <- tweedie.profile( y~1, p.vec=seq(1.1, 1.9, length=9), do.plot=TRUE) 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 .Error in .Fortran(.NAME = "pdfun", as.double(power), as.double(phi[i]/(y[i]^(2 - : supplied argument name '.NAME' does not match 'name' Calls: tweedie.profile -> dtweedie....

Dear Catarina, I prefer to leave the AIC value as NA for the tweedie GLM family because it takes extra time to compute and is only occasionally wanted. It's easy to compute the AIC yourself using the dtweedie() function of the tweedie package. Best wishes Gordon At 03:05 AM 14/08/2007, Catarina Miranda wrote: >Dear Gordon; > >I have also sent this...

Dear R-users, I'm trying to model some data using a tweedie GLM approach. My response variable is the number of pupae that are the offspring of a subordinate wasp on a wasp's nest. However, they're not count data- for each nest, I only know the mean number of pupae per subordinate, which is continous. The data also contain a high proportion of zeros...

Dear R users; I am modelling densities of some species of birds, so I have a problem with a great ammount of zeros. I have decided to try GLMs with the tweedie family, but in all the models I have tried I got an NA for the AIC value. Just to check the problem I've compared the a glm using the Gaussian family with the identity link and a glm using the tweedie family with var.power=0 and link.power=1. These are equal, as expected, except the fact that...

...M and I'm not completely sure I'm doing things right. As I said in a previous message my response variable is continuous with many zeros, so I was having a hard time finding an appropriate error distribution. I read some previous help mails given to other people advising them to use the Tweedie distribution. I'm still not sure if this would be appropriate for my data set, for I'm a beginner and really don't follow all the details. So I ran a GLMM using this distribution. I ran it for several models to do later model selection with AIC. I used the following script, where th...

Hi there, I'm using the tweedie distribution package and I cant figure out how to run a model using an identity link. I know I can use a log link by having link.power=0 and I think identity would be link.power=1, but I'm not sure. Furthermore when I try running it with link.power=1 it requires starting values which I cant...

Post-hoc test for a zero inflated continuous data set with a tweedie distribution? I have a zero inflated continuous data set of aphid feeding duration on 10+ species of plant. I have fitted a glm model with a tweedie distribution and used anova() function to show that there is significance between the plant species. However, I would now like to perform of post-hoc...

Good afternoon My name is Joanne Lenehan, I am a post grad at UNE using R version 2.9.0 I came across the Tweedie package in old R help posts and was interested in giving it a go for some data. The data is below and also attached as BaregroundLitterLogs Site Treatment Graze Dam Plot Time Bare Litter Logs 1 C remote yes 1 A 0 2 0 1 C remote yes 2 A 0 15 0 1 HE remote yes 1...

...<https://stat.ethz.ch/mailman/listinfo/r-help> 801.408.8111 I am not using R at the moment (working in SPSS, have to love the GUI) but my question is quite related: I am running a generalized linear model on data highly skewed to the right with a bunch of zeroes, so I decided to use the Tweedie distribution. In the model I ran both untransformed data (with link=log) as well as log(x+1) transformed data (with link=identity). The latter model had a much smaller (more negative) AICc value than the untransformed data with link=log. Is it valid to run the GLM with log(x+1) transformed data i...

...string apart at ":" and assign the result to a 2-tuple, and this results in a python error if the split results in three or more strings. The fix is to split only at the first ":", and then to split again if we detect "tap:" as the image type. Signed-off-by: Stephen Tweedie <sct@redhat.com> diff -r 94df5bd84195 -r aeba3dd98fbb tools/python/xen/util/blkif.py --- a/tools/python/xen/util/blkif.py Thu Sep 28 17:09:09 2006 +0100 +++ b/tools/python/xen/util/blkif.py Thu Sep 28 18:05:08 2006 +0100 @@ -64,9 +64,11 @@ def blkdev_uname_to_file(uname): ""&q...

...ewed. So I can't use gamma because of the zeros and since poisson is for count data I would probably loose lots of info when converting my data to integers. I was looking in the help archive of R and I realized that somebody had a similar problem in the past and was adviced' to use the Tweedie distribution since it was developed specifically for dealing with positive continuous data with exact zeros. I think this would be appropriate for my problem as well, but I'm not sure. I realized in the Tweedie help page that one can use a specific response distribution (Normal, Poisson, C...

...GLM with random effects. I have 3 replicates ('Replicate) of counts of parasites ('nor.tot.lep') before and after an experiment ('In.Out'). When I run lmer I get the error messages (16 of each) below... > lmer(nor.tot.lep ~ In.Out + (In.Out|Replicate),data=coho, family =tweedie(var.power = 1, + link.power = 1)) Generalized linear mixed model fit using PQL Formula: nor.tot.lep ~ In.Out + (In.Out | Replicate) Data: coho Family: Tweedie(mu^1 link) AIC BIC logLik deviance 849.2 867.4 -419.6 839.2 Random effects: Groups Name Variance Std.Dev. Corr Replicate (Intercept) 0.78861...

Dear all, I am interested in correctly testing effects of continuous environmental variables and ordered factors on bacterial abundance. Bacterial abundance is derived from counts and expressed as percentage. My problem is that the abundance data contain many zero values: Bacteria <-

Stephen, OK, I can now reproduce this hang at will, purely by pulling the plug on my desktop when logged in and then rebooting - its a gnome desktop box with few partitions and ext3 on all of them, so I guess its getting a pile of gnome or ssh related sockets kept in /tmp which is on root To recap, when the machine is suffering from this, it hangs at the point of mounting the root filesystem

...ondering if someone having experience working with large data sets would share the configurations and options he is using. If that matters here is the model I was trying to fit. library(package = "statmod", pos = 2, lib.loc = "/home/jeg002/R-1.8.1/lib/R/R_LIBS") qc.B3.tweedie <- glm(formula = pp20B3 ~ ageveh + anpol + categveh + champion + cie + dossiera + faq13c + faq5a + kmaff + kmprom + nbvt + rabprof + sexeprin + newage, family = tweedie(var.power = 1.577, l...

.../MAINTAINERS 2007-02-14 13:18:54.000000000 +0900 @@ -1283,7 +1283,7 @@ ETHERNET BRIDGE P: Stephen Hemminger M: shemminger@linux-foundation.org -L: bridge@osdl.org +L: bridge@lists.osdl.org W: http://bridge.sourceforge.net/ S: Maintained @@ -1298,13 +1298,13 @@ EXT3 FILE SYSTEM P: Stephen Tweedie, Andrew Morton -M: sct@redhat.com, akpm@osdl.org, adilger@clusterfs.com +M: sct@redhat.com, akpm@linux-foundation.org, adilger@clusterfs.com L: linux-ext4@vger.kernel.org S: Maintained EXT4 FILE SYSTEM P: Stephen Tweedie, Andrew Morton -M: sct@redhat.com, akpm@osdl.org, adilger@clusterfs.com...

I read the past archives by Stephen Tweedie regarding this error in 7.2 and in kernels prior to the 2.4.18-4 errata update. Since this is the only error I am experiencing (running 2.4.18-3), and I am feeling too lazy to patch all of our systems, do you feel it is necessary to patch the entire kernel to 2.4.18-4 or above, or is there a pa...

Hi there, My question is about the 'theta' parameter in specification of a NB GAMM. I have fit a GAM with an optimum structure of: SB.gam4<-gam(count~offset(vol_offset)+ s(Depth_m, by=StnF, bs="cs")+StageF*RegionF, family=negbin(1, link=log), data=Zoop_2011[Zoop_2011$SpeciesF=='SB',]) However, this GAM shows heterogeneity in the

Hello everybody, Could someone please explain to me what is the difference between kjournald and jbd (precisely, what does each of them do?) Thank you, Alina _________________________________________________________________ Chat with friends online, try MSN Messenger: http://messenger.msn.com