Monthly Archives: May 2010

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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