search for: tweedy

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|

Hi all I've been getting some emails from the R package maintainers that I need to update some code in a CRAN packge that uses FORTRAN, to comply with (not so recent) changes. I've been a little busy... I'm having trouble adjusting my code. I hope someone can help. The package was working fine, and a few R functions in my package had lines like this: tmp <- .Fortran(

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 email to R help mailing list,

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. I'm not very experienced at

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

Hi there, I've been wanting to fit a GLMM 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

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 manage to give appropriately so I'm not sure if its

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 test, ideally a Tukey-Kramer

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

Hi Dr. Snow, I am a graduate student working on analyzing data for my thesis and came across your post on an R forum: The default link function for the glm poisson family is a log link, which means that it is fitting the model: log(mu) ~ b0 + b1 * x But the data that you generate is based on a linear link. Therefore your glm analysis does not match with how the data was generated

If a Xen guest has a bootloader configured, then it will fail to start on a blktap image. The problem is blkdev_uname_to_file, which cannot parse the "tap:aio:$filename" image strings: it tries to split the 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

Hello there, I was wondering if somebody could offer me some advice on which error distribution would be appropriate for the type of data I have. I'm studying what continuous predictor variables such as grooming received, rank, etc. affect the amount of grooming given. This response variable is continuous with many zeros, and so positively skewed. So I can't use gamma because of the

Hi R-users: New to R and I am trying to run a 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

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

Hello R-users, First my settings: R-1.8.1, compiled as a 64bit application for a Solaris 5.8, 64 bit. The OS has 8Gb of RAM available and I am the sole user of the machine, hence pretty much all the 8Gb are available to R. I am pretty new to R and I am having a hard time to work with large data sets, which make up over 90% of the anlyses done here. The data set I imported in R, from S+, has a

Hi, I'm not sure if this is apprriate or not, but here goes anyway. The patch below updates MAINTAIER address Individuals (Only Andrew :): osdl.org -> linux-foundation.org Lists: osdl.org -> lists.osdl.org I assume the latter will change at some stage, but at least with this change the osdl/linux-foundation lists are consistent. Signed-off-by: Simon Horman

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 patch specific to the ext3 filesystem that could be

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