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Hello, The quick version of my question is how can I extract a matrix instead of a vector using tapply()? I would like to be able to access both the results of tapply() and also the index variables. In case...

Hello, I have a question regarding estimation of the dispersion parameter (theta) for generalized linear models with the negative binomial error structure. As I understand, there are two main methods to fit glm's using the nb error structure in...

It worked wonderfully - Thanks very much! hesicaia wrote: > > Hi all, > I have a question regarding subsetting of large data frames. I have two > data frames ?catches? and ?tows? and they both have the same 30 variables > (columns). I would like...

Hi all, I have a question regarding subsetting of large data frames. I have two data frames ?catches? and ?tows? and they both have the same 30 variables (columns). I would like to select rows in the data frame ?tows...

Bill.Venables wrote: > > Whoa! Just hang on a minute. > > theta is NOT the dispersion parameter. Under the NB model, the variance > of an observation is mu+mu^2/theta, so that's how theta enters the > picture. The smaller theta...

jholtman wrote: > > Working code would help. I would probably use 'lapply' since it > appears that you want to return a variable number of items for each > condition. > > On Tue, Jul 8, 2008 at 2:23 PM, hesicaia <dboyce at dal...

Hi, I have 2 questions, both pertaining to additive mixed models using mgcv(). I have fit several additive mixed models using the mgcv package (v 1.4) in R (v 2.8) modeling log chlorophyll as follows: mod<-try(gamm...

Hello, I have a specific question regarding figure layout. I am tryng to make a 2 by 1 figure but I would like to make the bottom figure slightly larger than the top figure. I have read through the help...