Treating outliers Introduction Outliers are the extreme values that a variable has, depending on the model or requirement, it could be necessary to treat them, either transforming or deleting. Variable “Income” distribution This is going to be our main variable in this example, which represents customer's income in $. We can ... [Read more...]

Today at the Davis R Users’ Group, Michael Koontz gave tour de force lesson in using R’s base graphics capabilities to plot data. Here’s the video: Get Michael’s excellent annotated script, which covers much more than we got to during our tutorial, here. [Read more...]

Shiny is an R application that allows users to build interactive web applications easily in R! Shiny apps involve two main components: a ui (user interface) script and a server script. The ui script controls the layout of the app and the server script controls what the app does. In ... [Read more...]

While movies have been getting more orange with time, painting have been going the other direction. Paintings today are generally more blue than they were a few hundred years ago. The image above shows the color spectrum of almost 100,000 paintings created since 1800. Martin Bellander used R to create the image, ... [Read more...]

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shinyjs is my second R package that managed to find its way past the CRAN review process. It lets you perform common useful JavaScript operations in Shiny applications without having to know any JavaScript. Demos You can check out a demo Shiny app that lets you play around with some ... [Read more...]

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by Joseph Rickert The New York Times is quietly changing the practice of science journalism. The Tuesday April 21, 2015 article: Ebola Lying in Wait, reports on "A growing body of scientific clues - some ambiguous, other substantive" that the Ebola virus may have lain dormant in West African rain forest for ... [Read more...]

Pandoc + markdown seem to be a great way of documenting my work. Markdown syntax is very simple and allows to add basic formatting and figures to an otherwise simple text document, without obfuscating the actual text. Then I simply compile the document using the pandoc command: There are some more ... [Read more...]

* If you see a bunch of [Math Processing Error] errors, you might want to try opening the page in a different browser. I have had some trouble with MathJax and Windows Explorer. There are various approaches to predicting Comrades Marathon finishing times. Lindsey Parry, for example, suggests that you use ... [Read more...]

Parallel Simulation of Heckman Selection Model One of the, if not the, fundamental problems in observational data analysis is the estimation of the value of the unobserved choice. If the (i^{text{th}}) unit chooses the value of (t) on the basis of some factors (mathbf{x_i}), which may ... [Read more...]

The R community is generally very fond of open-source-ness and the idea of releasing all code to the public. Writing packages has become such an easy experience now that Hadley's devtools is so powerful, and as a result there are new packages being released by useRs every single day. A ... [Read more...]

  Here’s a mostly useless visualization of the collection of journal articles that sits in my reference database in Endnote. I deal mostly in marine biology, physiology, biomechanics, and climate change papers, with a few molecular/genetics papers thrown in here and there. The database has 3325 entries, 2 of which have ... [Read more...]

The choice modeler looks over the adjacent display of cheeses and sees the joint marginal effects of the dimensions spanning the feature space: milk source, type, origin, moisture content, added mold or bacteria, aging, salting, packaging, price, and m... [Read more...]

Many graphs use a time series, meaning they measure events over time. William Playfair (1759 - 1823) was a Scottish economist and pioneer of this approach. Playfair invented the line graph. The graph below–one of his most famous–depicts ho... [Read more...]

My htmlTable-function has perhaps been one of my most successful projects. I developed it in order to get tables matching those available in top medical journals. As the function has grown I've decided to separate it from my Gmisc-package into a separate package, and at the time of writing this ... [Read more...]

The central quantity in Bayesian inference, the posterior, can usually not be calculated analytically, but needs to be estimated by numerical integration, which is typically done with a Monte-Carlo algorithm. The three main algorithm classes for doing so are Rejection sampling Markov-Chain Monte Carlo (MCMC) sampling Sequential Monte Carlo (SMC) ... [Read more...]