WelshPerm <- function(response,variable,nperm=999,...){ base <- oneway.test(response~variable,...) base.p <- base$p.value base.W <- base$statistic count <- 1 # Permutation loop for(i in 1:nperm){ SAMPLE <- sample(response) we...

Regular readers of this blog (yes, both of you!) may remember the computer/broadband/ directory that this post appears in as the collection of my Comcastic (yeah right) experiences with my ISP. But I think this week may top everything. I'll just...

Regular readers of this blog (yes, both of you!) may remember the computer/broadband/ directory that this post appears in as the collection of my Comcastic (yeah right) experiences with my ISP. But I think this week may top everything. I'll just try t...

Regular readers of this blog (yes, both of you!) may remember the computer/broadband/ directory that this post appears in as the collection of my Comcastic (yeah right) experiences with my ISP. But I think this week may top everything. I'll just...

Last week, I attended the 2006 UseR! conference: here is a (long) summary of some of the talks that took place in Vienna -- since there were up to six simultaneous talks, I could not attend all of them... In this note: 0. General remarks 1. Tutorial:...

I have just uploaded the new version of my "Statistics with R": http://zoonek2.free.fr/UNIX/48_R/all.htmlThe previous version was one year and a half old, so in spite of the fact I have not had much time to devote to it in the past two years, it might...

R only does natural (neperian) log scales by default, and this is lame. Here is a simple code to do decimal log scale, pretty much a requirement for scientists… The force(x/y)lim options works for natural and log scales (for the later case, you need to specify the power of 10 that you want : c(-2,2)

Lane Kenworthy, Yu-Sung Su, and I write: Income inequality in the United States has risen during the past several decades. Has this produced an increase in partisan voting differences between rich and poor? We examine trends from the 1940s thr...

I found a description of supposed to be profitable strategy on Bloomberg. The strategy is simple – buy S&P500 index on close and sell it on next day open. So, I tested this claim and got nice P/L curve: Yes, since 1993 this strategy has generated the profit >300%. But, neither commissions or slippage are included:) Let’s

Producing this kind of graphs (below) in R can be a pain in the a*s. Here is a simple code that requires that data are presented in lists (see the example below). multbar <- function(list.of.lists,...,condnames=0,pal=colorRampPalette(c('grey','cornsilk')),seriesnames=0,legendpos='topleft',legh=TRUE,do.pty='s') { par(pty=do.pty,mgp=c(1.9,0.8,0),oma=c(0,0,0,0),mar=c(4,3,2,1),bg='transparent',bty='o',tck=0.02,yaxs='i') NofList <- length(list.of.lists) NofSubList <- length(list.of.lists]) if(condnames==0){condnames=c(1:NofList)} if(seriesnames==0){seriesnames=c(1:NofSubList)} dim.mat.treat <- (NofList+1)*NofSubList pos <- c(1:dim.mat.treat) pos <- matrix(pos,nrow=(NofList+1)) nbreaks

This post will eventually grow to hold a wide list of books on statistics (e-books, pdf books and so on) that are available for free download. But for now we’ll start off with just one several books: The Elements of Statistical Learning written by Trevor Hastie, Robert Tibshirani and Jerome Friedman. you can legally download

Permutation tests (section 2.4.3) are a form of resampling based inference that can be used to compare two groups. A simple univariate two-group permutation test requires that the group labels for the observations are exchangeable under the null hypothesis of equal distributions, but allows relaxation of specific distributional assumptions required by parametric procedures such as the t-test (

This is a step-by-step guide to 'Sweave' a document in R with Lyx on Ubuntu (9.04).System: Ubuntu 9.04, LyX 1.6.2, R 2.11.0 (Development version, r50178)Install LyX with Synaptic if it is not installed yet. (Current version 1.6.2)Start LyX, go to menu ...

Some things I write in perl some in R, sometime I use perl to write R and run R. One thing that I find very useful is the functionality of RSPerl which enables you to call R functions from within perl and on perl variables. It can also call perl from R, though I have no idea why...

Some things I write in perl some in R, sometime I use perl to write R and run R. One thing that I find very useful is the functionality of RSPerl which enables you to call R functions from within perl and on perl variables. It can also call perl from R, though I have no idea why...