similar to: On guessing theta

Hi, I am a bit stuck on specifying ui and ci. I have read Lange's book ((1999) Numerical Analysis for Statisticians) to his approach and unfortunately his descriptions were not helpful for me. Here is what I have: ui <- rbind(c(0, -1, 0), c(0, 0, -1)) ci <- c(0, -1, -1)) theta <- c(0.5, 0.5, 0.1) My goal is to feed these into constrOptim

Hello, I am working on the frailty model using coxph functions. I am running some simulations and want to store the variance of frailty (theta) values from each simulation result. Can anyone help me how to extract the theta values from the results. I appreciate any help. Thanks Shankar Viswanathan

I am fitting a negative binomial regression model to some count data. I chose the negative binomial b/c the variance is greater than the mean. Anyways, when I fit the model I get the following warning: "Warning while fitting theta: alternation limit reached" The estimate that I end up with is very large (1070), and the standard error is even larger (1276). Does this indicate that I

Dear all, Does the frailty.object$history[[1]]$theta returns the Variance of random effect? Why is the value different? Here is an example with kidney data: > library(survival) > data(kidney) > frailty.object<-coxph(Surv(time, status)~ age + sex + disease + frailty(id), kidney) > frailty.object Call: coxph(formula = Surv(time, status) ~ age + sex + disease + frailty(id), data

Dears, Oracle 8 don''t support ANSI syntax with : SELECT e.emp_id, e.fname, e.lname, j.jobdesc FROM employe e LEFT JOIN jobs j ON e.job_id = j.job_id but only SELECT e.emp_id, e.fname, e.lname, j.jobdesc FROM employe e, jobs j WHERE j.job_id (+) = e.job_id JOIN syntax came with 9i. Anyone patched Rails

Dear All, Consider the following code: plot(0,0) text(0,0.5,expression(italic(theta))) I would like to get theta in italic, but I always get it upright. Any suggestions? Thanks in advance, Paul

I am using package LTM to estimate a Rasch model: irtestimates <- rasch(binRasch) I want to get a single vector containing theta estimates for all the rows (individuals) in my data matrix (hopefully in the same order as my data matrix) such that the length of the theta vector = the number of rows (participants) in my data matrix. I am using: theta.est <-

Dear R users, I am trying to use "gamm" from package "mgcv" to model results from a mesocosm experiment. My model is of type M1 <- gamm(Resp ~ s(Day, k=8) + s(Day, by=C, k=8) + Flow + offset(LogVol), data=MyResp, correlation = corAR1(form= ~ Day|Mesocosm), family=poisson(link=log)) where the response variable is counts, offset by the

Hi all, what indicates the parameter theta in the summary of a random effect panel model estimated with the plm function? example: data("Produc", package = "plm") zz <- plm(log(gsp) ~ log(pcap) + log(pc) + log(emp) + unemp, model="random", data = Produc, index = c("state","year")) summary(zz) Effects: var std.dev

Hi, I'm trying to use the command "glm.nb" in library(MASS) to test for a significant difference in the aggregation parameter "theta" between the three levels of a factor. Any help gratefully received! Martin. Martin Hoyle, School of Life and Environmental Sciences, University of Nottingham, University Park, Nottingham, NG7 2RD, UK Webpage:

I set sshd to deny root login. But I still get a password prompt! So if I get the password right, I get one error message: Received disconnect: ROOT LOGIN REFUSED FROM example.com while if I simply put in a wrong password three times I get Permission denied. If this means I set it up wrong please mail me directly - I'm not subscribed to the list. Otherwise please fix this. -- The

Hi, I was using F-Secure SSH V2.0 client to connect openssh server. Here the relevant part of the client log. ----------------------------------------------------- local ip = 172.168.29.8, local port = 4870 remote ip = 172.168.29.7, remote port = 22 remote hostname is "172.168.29.7". Wrapping... Remote version: SSH-2.0-OpenSSH_3.2.2p1 CBVersionCheck: remote version

Recently I grew tired of the repeated ssh brute-force scanning bots so I implemented a blocking algorithm in our version of OpenSSH. My goal was to find an algorithm which could block most of the brute-force attempts while being simple to implement and not rely on any external software. The algorithm I came up with is that login attempts are blocked if there has been X failed, and no successful,

A while ago I wrote a numbers guessing game to keep me entertained on those really boring days :). I've uploaded it to the blog for the rest of you to enjoy or modify as well. It's a simple game to guess what number the PBX is thinking of and return a "yay you got it right" or a "sorry that's wrong". All sound files are included and ready to add to your system in a

Dear List, I am trying to do model averaging for a negative binomial model using the package AICcmodavg. I need to use glm() since the package does not accept glm.nb() models. I can get glm() to work if I first run glm.nb and take theta from that model, but is there a simpler way to estimate theta for the glm model? The two models are: mod.nb<-glm.nb(mantas~site,data=mydata)

Dear R Users, When using zeroinfl() function to fit a Zero-Inflated Negative Binomial (ZINB) model to a dataset, the summary() gives an estimate of log(theta) and its standard error, z-value and Pr(>|z|) for the count component. Additionally, it also provided an estimate of Theta, which I believe is the exp(estimate of log(theta)). However, if I would like to have an standard error of Theta

I am running 9 negative binomial regressions with count data. The nine models use 9 different dependent variables - items of a clinical screening instrument - and use the same set of 5 predictors. Goal is to find out whether these predictors have differential effects on the items. Due to various reasons, one being that I want to avoid overfitting models, I need to employ identical types of

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

How might you fit a generalized linear model (glm) with variance = mu+theta*mu^2 (where mu = mean of the exponential family random variable and theta is a parameter to be estimated)? This appears in Table 2.7 of Fahrmeir and Tutz (2001) Multivariate Statisticial Modeling Based on Generalized Linear Models, 2nd ed. (Springer, p. 60), where they compare "log-linear model fits to

Hi again, I have the following scenario: I've got a partition which has exactly 14659312 blocks: $ fdisk -l /dev/hda Disk /dev/hda: 28.5 GB, 28520497152 bytes 255 heads, 63 sectors/track, 3467 cylinders Units = Zylinder of 16065 * 512 = 8225280 bytes Ger?t Boot Start End Blocks Id System (...) /dev/hda4 1643 3467 14659312+ 83 Linux (...)