Say I have a formula Y ~ 1 + X, where X is a categorical variable. A previous thread showed how to evaluate this model using the mle package from "stats4" (see below). But, the user had to create the data matrix, X, including the column of one's for the regression constant. Is there a way to nest the linear formula in the code below, so the data matrix doesn't explicitly have to be created by the user?
Y <- c(0,0,1,0,0,1,1,0,0,0,0,1,1,0,1,1,0,1,1,0,1) X <- cbind(matrix(1,21,1),matrix(c(-48.5,24.4,82.8,-24.6,-31.6,91.0,52.1,-87.7,-17.0,-51.5, -90.7,65.5,-44.0,-7.0,51.6,32.4,-61.8,34.0,27.9,-72.9,49.9), 21,1)) log.lo.like <- function(beta,Y,X) { Fbetax <- 1/(1+exp(-beta%*%t(X))) loglbeta <- -log(prod(Fbetax^Y*(1-Fbetax)^(1-Y))) } #####Using MLE##### ll <- eval(function(beta0=0,beta1=0) log.lo.like (c(beta0,beta1),Y,X), list(X=X,Y=Y)) summary(mle(ll)) ####Comparison using glm##### glm(Y~X-1,family=binomial) Thanks, Stephen Collins, MPP | Analyst Global Strategy | Aon Benfield [[alternative HTML version deleted]] ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.