Publications by PirateGrunt
An idiot learns Bayesian analysis: Part 1
I've done a dreadful job of reading The Theory That Would Not Die, but several weeks ago I somehow managed to read the appendix. Here the author gives a short explanation of Bayes' theorem using statistics related to breast cancer and mammogram results. This is the same real world example (one of several) used by Nate Silver. It's profound in its...
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An idiot learns Bayesian analysis: Part 2
A week ago, I wrote a bit about my personal journey to come to grips with Bayesian inference. I referred to the epiphany that when we're talking about Bayesian analysis, what we're talking about- in a tangible way- is using and modifying multivariate distributions. This reminds me of the moment, about twenty years ago now, when I had a nascent in...
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Another skewed normal distribution
At the CLRS last year, Glenn Meyers talked about something very near to my heart: a skewed normal distribution. In loss reserving (and I'm sure, many other contexts) standard linear regression is less than ideal as it presumes that deviations from the mean are equally distributed. We rarely expect this assumption to hold (though we should always ...
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Recursive assignment
Here’s yet another example where I just need to read the help files. Before I go on, I should add my own notion as to why that’s not always easy to do. On loads of message boards, you’ll see people say- correctly- that the documentation is very clear on XYZ. True. But that’s only relevant if you read the bit of the documentation that actu...
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Stuff I’ve gotten horribly wrong
I'm the first (I hope) to admit when I've gotten something wrong. I like to think I'm humble enough to realize that there are limits to my knowledge. Actually, humility doesn't enter into it. Every day I'm confronted with things that I don't know or understand. Those same limits can often blind me to being sage enough to recognize when I've gone ...
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An Idiot Learns Bayesian Analysis: Part 3
A week or so ago, the grand Magus over at lamages.blogspot.com/ published a great, quick thought exercise taken from Daniel Kahneman’s book Thinking, Fast and Slow. Here are the particulars of the problem: you’re in a community with two different color vehicles; 85% are green and 15% are blue. A vehicle was involved in a hit and run accident....
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Visualizing the History of Epidemics
I really like National Geographic. Their magazine is great, their television documentaries are done well and they helped give me a lifelong love of maps. They generate very good information and help shed light on the world we all share. So why is this graphic so awful? Let's have a look: We'll start off by saying that no one will mistake me for ...
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Makefiles and RMarkdown
Quite some time ago (October 2013, according to Amazon), I bought a copy of “Reproducible Research with R and RStudio” by Christopher Gandrud. And it was awesome. Since then, I’ve been using knitr and RMarkdown quite a lot. However, until recently, I never bothered with a makefile. At the time, I had assumed that it was something only avail...
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