# Monthly Archives: December 2009

## R Site Search with the ‘sos’ Package

December 15, 2009
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REvolution Computing is a sponsor of the Bay Area R User Group, which gathered on Tuesday for its monthly meeting. This month's meeting was in a cozy setting at San Jose State University, and was hosted by David Czerwinski who teaches data mining there. The topic at hand was search, and finding R packages to compliment the functionality requirements...

## Browse R Graphics with the R Graph Gallery and the R Graphical Manual

December 15, 2009
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One of R's biggest strengths is its unparalleled graphing capabilities.  Just see any of our previous posts on ggplot2, visualization, or other posts tagged with R. R has several fundamentally different systems for plotting, including base graphics, lattice, and ggplot2.  Furthermore, many add-on packages come with their own functions for producing problem-domain specific graphics. For example,

## R Tutorial Series: Graphic Analysis of Regression Assumptions

December 15, 2009
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An important aspect of regression involves assessing the tenability of the assumptions upon which its analyses are based. This tutorial will explore how R can help one scrutinize the regression assumptions of a model via its residuals plot, normality h...

## Object-Oriented Programming in R: The Setter Methods

December 14, 2009
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With a little guidance from the indefatigable Hadley Wickham, I figured out today how to implement the setter methods that were missing from my example user class. To review, let’s rebuild the getter methods for my user object: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

## NYT on breast cancer screening and probability

December 14, 2009
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The New York Times last weekend looked at the controversy around the recent changes to the mammogram guidelines from a mathematical perspective. Compared to the analysis based on Bayes' Theorem from the Harvard Social Science Statistics blog (which apparently caused some controversy itself: that post was deleted and later replaced after some errors apparently crept into the calculations), this...

## The Grammar of Graphics: ggplot2 package

December 14, 2009
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The grammar of graphics approach to constructing graphs has been implemented in the ggplot2 package in R. The author of the package, Hadley Wickham, has provided a website with many details of using the system to create nice looking graphics. The package removes many of the awkward parts of setting up graphical display that characterise other

## R 2.10.1 released

December 14, 2009
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The latest update to R, R 2.10.1, is now available for download in source form from your local CRAN mirror. Binary versions (for Mac, Windows, and Linux) will become available over the next few days. As a maintenance release, this update focuses on minor changes and bug fixes. The complete list of changes is available in the NEWS file,...

## Example 7.18: Displaying missing value categories in a table

December 14, 2009
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When displaying contingency tables (section 2.3.1), there are times when it is useful to either show or hide the missing data category. Both SAS and the typical R command default to displaying the table only for observations where both factors are observed.In this example, we generate some multinomial data (section 1.10.4) and then produce tables with and without...

## RQuantLib 0.3.1 released

December 13, 2009
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A new version of RQuantLib is now out at CRAN and in Debian. It updates the package to the 0.9.9 release of QuantLib and is mostly a maintenance release with a few minor fixes along the way. Full changelog details, examples and more details abo...

## Galton’s quincunx in R

December 13, 2009
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Andrej Blejec has a very nice R demo of Galton's quincunx (link1, link2). It is a bit tedious to copy the code from PDF to R console, but it is worth the effort as the demo simulation clearly shows the nature of quincunx. After a bit of search I also f...