I was impressed by Stack Exchange’s recent announcement of their machine learning system, Providence, that guesses what kind of programmer you are based on your Stack Overflow traffic. Stack Exchange uses this to choose what questions to show you on their homepage and to recommend jobs to you in ... [Read more...]

I recently came across this question on Cross Validated, and I thought it offered a great opportunity to use R and ggplot2 to explore, in depth, the assumptions underlying the k-means algorithm. The question, and my response, follow. K-means is a widely used method in cluster analysis. In my understanding, ... [Read more...]

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I have some experience teaching R programming (see, for instance, my online course). One of the atypical choices I make is to start by teaching Hadley Wickham’s ggplot2 package, rather than the built-in R plotting (see these videos). Many times that I mention this choice to others involved in ... [Read more...]

I spend a good amount of time on the programming Q+A site StackOverflow (and a smaller amount of time on its statistics sister site, Cross Validated). Recently this question on Meta Stack Overflow (the website’s discussion forum) caught my attention, raising the question of whether Stack Overflow had ... [Read more...]