search for: reyhan

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 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, 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?