[R] covariance matrix of predictions

Hi ! I am trying to get at the covariance of the predictions of a linear model. Suppose the we have: x-runif(1000) y-2 + 25x*x +rnorm(1000) lm1 -lm(y~x, data = data.frame(y = y, x=x)) x.pred -runif(10) y.hat - predict(lm1, newdata = data.frame(x=x.pred)) I was wondering how to get an

[R] factors

Hi R-users, I had a minor issue while demonstating R that I can't explain. I am hoping someone will have suggestions. The only difference is a call to fix() in between that I made to ensure people were following me. However, that seems to have altered the way R code got executed. I was

[R] Dynamic Programming in R

Hi R users, I am looking to numerically solve a dynamic program in the R environment. I was wondering if there were people out there who had expereinced success at using R for such applications. I'd rather continue in R than learn Mathlab. A concern that has been cited that may discourage R

[R] Sweave +RWinEdt

Hi! I was just reading Uwe Ligges write up on extending R-WinEdt for Sweave from 2003; I was wondering if there were updates on it? Are people seriously thiking about it? I really use WinEdt a lot, and for not just R, and hence this kind of extension would be really cool for a whole range

[R] Probit predictions outside (0,1) interval

Hi! I was trying to implement a probit model on a dichotomous outcome variable and found that the predictions were outside the (0,1) interval that one should get. I later tried it with some simulated data with a similar result. Here is a toy program I wrote and I cant figure why I should be

[R] Confirmatory Factor Analysis in R? SEM?

Hi Has anyone used R to conduct confirmatory factor analysis? This email pertains to use of SEM. For context consider an example: the basic idea is that there are a bunch of observables variables (say study habbits, amount of time reading in the bus, doing homework, helping other do

[R] Rd.sty not found -

Hi I am still trying to wrap up a package using Rcmd (in windows 2000 professional with R 1.8.1). I have made some progress - and now at least Rcmd check works - it still giving me an error message when it creates latex help files though. Thus I get: c:\rpack Rcmd check test * checking for

[R] R-package install

Hi I have been trying to get the R Extention supportware going for a while now and have been running to an error I cannot figure out. I am hoping someone here will recognize whats going on and what i may be messing up. After installing all the components - Rtools, Active Perl, and minGW I

[R] write.dta and handling labels

Hello, I need to write out a data matrix as a STATA 7 file and this happens perfectly with write.dta(), except I cannot seem to export the labelnames to Stata. So far I have tried the following: # X is the data matrix that is to be exported attributes(X)$var.labels - c(apple, banana, cat)

[R] RWinEdt patch

Hi: I just tried to install the patch for RWinEdt - there is an automated package ('SWinRegistry' ) which with the rwinedt patch on the CRAN site have to be loaded as packages from R using the local zip drive option. That works fine. The next step is to call the library(RwinEdt) and this