Recently I was looking to buy a used car. I was using the Edmunds website to estimate the true market value of a used car. It has a nice click through interface where it guides you to input make, model, … Continue reading →

This coming Tuesday, August 27, our US Chief Scientist Mario Inchosa will reveal some details of the forthcoming in-Hadoop predictive analytics capabilities of Revolution R Enterprise 7, due for release later this year. Here's the abtract of his webinar, High Performance Predictive Analytics in R and Hadoop: Hadoop is rapidly being adopted as a major platform for storing and...

One critique frequently heard about Bayesian statistics is the subjectivity of the assumed prior distribution. If one is cherry-picking a prior, of course the posterior can be tweaked, especially when only few data points are at hand. For example, see the Scholarpedia article on Bayesian statistics: In the uncommon situation that the data are extensive

People love $R^2$. As such, when Nakagawa and Schielzeth published an article in the journal Methods in Ecology and Evolution earlier this year, ecologists (amid increasing use of generalized linear mixed models (GLMMs)) rejoiced. Now there’s an R function that automates $R^2$ calculations for GLMMs fit with the lme4 package. $R^2$ is usually reported as a...

Importing DatesDates can be imported from character, numeric, POSIXlt, and POSIXct formats using the as.Date function from the base package.If your data were exported from Excel, they will possibly be in numeric format. Otherwise, they will m...

About a year ago I posted this video visualization of all the reported accidents involving bicycles in Montreal between 2006 and 2010. In the process I also calculated and plotted the accident rate using a monthly moving average. The results followed a pattern that was for the most part to be expected. The rate shoots up

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