search for: bhatticr

Hello, I am not sure what to write in the subject line, but I would like to take a character string that is a variable in a data frame and apply a function that takes a numeric argument to this character string. Here is a simplified example that would solve my problem. Imagine I have my data stored in a data frame. > x1 <- x2 <- x3 <- x4 <- x5 <- rnorm(20,0,1); > data <-

Hello, I have a question about the add1() function and quasilikelihoods for GLMs. I am fitting quasi-Poisson models using glm(, family = quasipoisson). Technically, with the quasilikelihood approach the deviance does not have the interpretation as a likelihood-based measure of sample information. Functions such as stepAIC() cannot be used. The function add1() returns the change in the scaled

Hello, I am creating a number of objects that I wish to have a common name with an index such as x1, x2, x3, ... I would like to do everyting in a loop to make the code compact and minimize the probability of an error by typo. A test problem may look like for (j in 1:10){ as.symbol(paste("x",j,sep="")) <- j; } which ideally would produce x1 = 1, ... x10 = 10. However,

Hello, I am not fluent in computer hardware or software development so I will try to be as precise as I can. I am going to build some R routines to analyze large intraday financial data sets. For this project I think that I need be concerned about R memory limits and good memory management/practices. The following R help page states that the limit on individual objects (a vector) is

Hello, My question concerns model selection, stepAIC(), add1(), and coxph(). In Venables and Ripley (3rd Ed) pp389-390 there is an example of using stepAIC() for the automated selection of a coxph model for VA lung cancer data. A statistics question: Can partial likelihoods be interpreted in the same manner as likelihoods with respect to information based criterion and likelihood ratio tests?

Hello, I am trying to compile some F77 subroutines as shared objects for R on my Mac. --> Mac OS-X Version 10.4.11 (Tiger Intel Mac) I have done this (successfully) before on Sun Solaris and Linux Fedora systems using the following command. > R CMD SHLIB myfile.f I have g77 installed from this page. http://hpc.sourceforge.net/ I am using R 2.8.1, and I have installed all 4 additional

> Hello, > > I have a question about a discrepancy between the > reported F statistics using anova() and add1() from > adding an additional term to form nested models. > > I found and old posting related to anova() and > drop1() regarding a glm with a dispersion parameter. > > The posting is very old (May 2000, R 1.1.0). > The old posting is located here. >