Example 7.38: Kaplan-Meier survival estimates

May 24, 2010
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Example 7.38: Kaplan-Meier survival estimates

In example 7.30 we demonstrated how to simulate data from a Cox proportional hazards model.In this and the next few entries, we expand upon support in R and SAS for survival (time-to-event) models. We'll start with a small, artificial dataset of 19 su...

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Rmetrics AMPL Interface

May 24, 2010
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(This article was first published on Rmetrics blogs, and kindly contributed to R-bloggers) To leave a comment for the author, please follow the link and comment on his blog: Rmetrics blogs. R-bloggers.com offers daily e-mail updates about R news and tutorials on topics such as: visualization (ggplot2, Boxplots, maps, animation), programming (RStudio, Sweave, LaTeX, SQL, Eclipse, git, hadoop, Web...

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THETA AG uses Rmetrics

May 24, 2010
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(This article was first published on Rmetrics blogs, and kindly contributed to R-bloggers) To leave a comment for the author, please follow the link and comment on his blog: Rmetrics blogs. R-bloggers.com offers daily e-mail updates about R news and tutorials on topics such as: visualization (ggplot2, Boxplots, maps, animation), programming (RStudio, Sweave, LaTeX, SQL, Eclipse, git, hadoop, Web...

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Introduction to using R with org-babel, Part 1

May 23, 2010
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This post originally appeared on my Wordpress blog on May 23, 2010. I present it here in its original form. In my opinion, the description of orgmode by its creator as a tool "for keeping notes, maintaining ToDo lists, doing project planning,...

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Introduction to using R with org-babel, Part 1

May 23, 2010
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This post originally appeared on my Wordpress blog on May 23, 2010. I present it here in its original form. In my opinion, the description of orgmode by its creator as a tool "for keeping notes, maintaining ToDo lists, doing project planning,...

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R Function of the Day: sample

May 23, 2010
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This post originally appeared on my Wordpress blog on May 23, 2010. I present it here in its original form. The R Function of the Day series will focus on describing in plain language how certain R functions work, focusing on simple example...

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R Function of the Day: sample

May 23, 2010
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This post originally appeared on my Wordpress blog on May 23, 2010. I present it here in its original form. The R Function of the Day series will focus on describing in plain language how certain R functions work, focusing on simple example...

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Code and brief instruction for graphing Twitter with R

May 23, 2010
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Code and brief instruction for graphing Twitter with R

Edit: I’ve posted an updated version of the script here. It is not quite as compressed as Anatol’s version, but I think it’s a decent compromise between readability and efficiency. Edit #2 And yet another update, this one contributed by Kai Heinrich. I hacked together some code for R last night to visualize a Twitter

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S4 timeDate Package

May 23, 2010
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(This article was first published on Rmetrics blogs, and kindly contributed to R-bloggers) To leave a comment for the author, please follow the link and comment on his blog: Rmetrics blogs. R-bloggers.com offers daily e-mail updates about R news and tutorials on topics such as: visualization (ggplot2, Boxplots, maps, animation), programming (RStudio, Sweave, LaTeX, SQL, Eclipse, git, hadoop, Web...

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Portfolio Risk Surfaces

May 23, 2010
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(This article was first published on Rmetrics blogs, and kindly contributed to R-bloggers) To leave a comment for the author, please follow the link and comment on his blog: Rmetrics blogs. R-bloggers.com offers daily e-mail updates about R news and tutorials on topics such as: visualization (ggplot2, Boxplots, maps, animation), programming (RStudio, Sweave, LaTeX, SQL, Eclipse, git, hadoop, Web...

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R Function of the Day: sample

May 23, 2010
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R Function of the Day: sample

The R Function of the Day series will focus on describing in plain language how certain R functions work, focusing on simple examples that you can apply to gain insight into your own data. Today, I will discuss the sample function. Random Permutations In its simplest form, the sample function can be used to return

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Stability Watch Views

May 22, 2010
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(This article was first published on Rmetrics blogs, and kindly contributed to R-bloggers) To leave a comment for the author, please follow the link and comment on his blog: Rmetrics blogs. R-bloggers.com offers daily e-mail updates about R news and tutorials on topics such as: visualization (ggplot2, Boxplots, maps, animation), programming (RStudio, Sweave, LaTeX, SQL, Eclipse, git, hadoop, Web...

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Variable selection using automatic methods

May 22, 2010
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When we have a set of data with a small number of variables we can easily use a manual approach to identifying a good set of variables and the form they take in our statistical model. In other situations we may have a large number of potentially important variables and it soon becomes a time

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Helping the blind use R – by exporting R console to Word

May 22, 2010
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Preface – R seems a natural fit for the blind statistician For blind people who wish to do statistics, R can be ideal. R command line interface offers straight forward statistical scripting in the form of question (what is the mean of x) followed by an answer (0.2). That is, instead of point-and-click dialog boxes with jumping windows of...

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Using R for Introductory Statistics, 3.1

May 21, 2010
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Using R for Introductory Statistics, 3.1

Pairs of categorical data The grades data.frame holds two columns of letter grades, giving pairs of categorical data, like so: prev grade 1 B+ B+ 2 A- A- 3 B+ A- ... 122 B B This type...

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The only thing smiling today is Volatility

May 21, 2010
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The only thing smiling today is Volatility

With the stock market freaking out and all, I figured I should take a look at how volatility was being priced in the option market. The CBOE generously provides snapshots of market data for anyone interested to download. By using this data, we can calculate the markets ‘implied volatility’, or level of ‘freaking

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Because it’s Friday: Ash

May 21, 2010
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I lived for 10 years within sight (on a clear day, anyway) of Mount St. Helens, and had seen and heard a lot about the devastation caused by the eruption and pyroclastic flow 30 years ago. But I'd heard relatively little about the effects of the ash cloud settling on land. I was surprised to learn about the effect...

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Color choosing in R made easy

May 21, 2010
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Color choosing in R made easy

I don’t know about you, but when I want to make a graph in R, I handpick the colors, line widths etc… to produce awesome output. A lot of my time is spent on color choosing, I had to find a more convenient way of doing so. Earl F. Glynn’s “Chart of R colors”  posted [&hellip

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R 2.11.1 scheduled for May 31

May 21, 2010
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As announced by the R Core Team, the next update to R will be 2.11.1 to be released on May 31. Despite being a minor-minor version increment, this release is expected to sport at least one new feature: BIC (in package stats4) will work with multiple fitted models, like AIC does. There will also be some improvements to the...

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Tip of the day: Keep the console active in R Productivity Environment

May 21, 2010
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Jared Lander on Twitter asks: When I alt-tab into R Enterprise how do I make the #rstats console the active window by default. Now it goes to solution explorer. Revolution's crack Support engineer Stephen Weller offers this solution: The best way to do this is to right-click on the R-Console window and make it a 'Tabbed Document'....

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Random sudokus [p-values]

May 21, 2010
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Random sudokus [p-values]

I reran the program checking the distribution of the digits over 9 “diagonals” (obtained by acceptable permutations of rows and column) and this test again results in mostly small p-values. Over a million iterations, and the nine (dependent) diagonals, four p-values were below 0.01, three were below 0.1, and two were above (0.21 and 0.42).

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highlight 0.1-8

May 21, 2010
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I've pushed version 0.1-8 of highlight to CRAN. highlight is a syntax highlighter for R that renders R source code into some markup language, the package ships html and latex renderers but is flexible enough to handle other formats. Syntax highligh...

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ACM Transactions on Modeling and Computer Simulation

May 20, 2010
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ACM Transactions on Modeling and Computer Simulation

Pierre Lecuyer is the new editor of the ACM Transactions on Modeling and Computer Simulation (TOMACS) and he has asked me to become an Area Editor for the new area of simulation in Statistics. I am quite excited by this new Æditor’s hat, since this is a cross-disciplinary journal: The ACM Transactions on Modeling and

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R: A random walk though OOP land.

May 20, 2010
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If you are used to object oriented programing in a different language, the way R does things can seem a little strange and backwards. “proto” to the rescue. With this library you can simulate “normal” OOP. I found the examples for proto not so helpful, so to figure out how the package works I sent

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Load Testing Think Time Distributions

May 20, 2010
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Load Testing Think Time Distributions

One of my gripes about some commercial load testing tools is that they only provide a think time distribution (Z) that is equivalent to uniform variates in the client-script. If you want some other distribution, you have to code it and debug it yoursel...

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Calling all T-shirt designers

May 20, 2010
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Got design skills as well as R skills? The organizers of the useR! 2010 conference are looking for a design to be used on the conference T-shirts. Mango Solutions (who are sponsoring the T-shirt) will select the winner, but personally I'd give extra points for designs that use R itself -- it's been done before! R-statistics blog: useR-2010 is...

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Tutorial: Principal Components Analysis (PCA) in R

May 20, 2010
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Found this tutorial by Emily Mankin on how to do principal components analysis (PCA) using R. Has a nice example with R code and several good references. The example starts by doing the PCA manually, then uses R's built in prcomp() function to do the s...

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RcppArmadillo 0.2.0 (and 0.2.1)

May 20, 2010
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With the Rcpp 0.8.0 release on Monday, Romain, Doug and I were able to follow-up with a new RcppArmadillo release. RcppArmadillo uses Rcpp (and a few dozen lines of 'glue') to provide a transparent interface from R to Conrad Sanderson's impressive Arma...

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RcppArmadillo 0.2.0 (and 0.2.1)

With the Rcpp 0.8.0 release on Monday, Romain, Doug and I were able to follow-up with a new RcppArmadillo release. RcppArmadillo uses Rcpp (and a few dozen lines of 'glue') to provide a transparent interface from R to Conrad Sanderson's impressive Arm...

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