Background In the forth coming week, I will be giving a presentation on the fundamentals of imputation to my colleagues. One of the most important idea I would like to present is multiple imputation. In my last post, I have...

by James Paul Peruvankal, Senior Program Manager at Revolution Analytics At Revolution Analytics, we are always interested in how people teach and learn R, and what makes R so popular, yet ‘quirky’ to learn. To get some insight from a real pro we interviewed Bob Muenchen. Bob is the author of R for SAS and SPSS Users and, with...

Correlation does not imply causation, sure but, as Edward Tufte writes, “it sure is a hint.” The Pearson product-moment correlation coefficient is perhaps one of the most common ways of looking for such hints and this post describes the Bayesian First Aid alternative to the classical Pearson correlation test. Except for being based on Bayesian estimation (a good...

The leave-one-out cross-validation statistic is given by where , are the observations, and is the predicted value obtained when the model is estimated with the th case deleted. This is also sometimes known as the PRESS (Prediction Residual Sum of Squares) statistic. It turns out that for linear models, we do not actually have to estimate the...

Numerous psychological studies have demonstrated that people often have an inflated perception of their personal qualities. From work performance to driving skills, people report being above average in relation to others when it comes to many arenas. This extends to how people perceive their own physical attractiveness and intelligence levels. This begs the important question: Are

by Joseph Rickert I am a book person. I collect books on all sorts of subjects that interest me and consequently I have a fairly extensive collection of R books, many of which I find to be of great value. Nevertheless, when I am asked to recommend an R book to someone new to R I am usually flummoxed....

Today’s email brought this one: I was wondering if I could get your opinion on a particular problem that I have run into during the reviewing process of an article. Basically, I have an analysis where I am looking at a couple of time-series and I wanted to know if, over time there was an upward trend in the...

It is our pleasure to once again offer the intensive R beginner level course for the third time! Beginning this Sunday, the 35 hour course will walk you through the basic operations and characteristics of R, all the way to having a firm understanding of data manipulation and visualization. Also launching this weekend are two... Read more »

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