therandomtexan
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R Tutorial: Correlation
Fisher’s iris dataset is the basis for this extended example in the calculation and visualization of correlations. The ggpairs() function gives an impressive coded scatterplot matrix. And an old friend makes a last-minute cameo appearance. Update: Dirk Eddelbuettel just released tint 0.0.3 (tint is not Tufte) with some nifty examples. I wanted to try it Read more
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Art Meets Science
On a day that I’m overbooked, running around campus doing minor, but essential chores, and feeling a bit grumpy about the whole academic enterprise, I stumble upon a jewel like this: Not in a gallery or the administration building, but in a hallway between classrooms. Where thousands of students, and the odd faculty member, can Read more
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Dang! Shut Out
I was disappointed that my alma mater and employer, UT at San Antonio, didn’t make the Texas Top 30 list, but then I followed up on the College Choice and found that UTSA didn’t make their Top 50 list either. Maybe this has something to do with it. Read more
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Chorizo, seriously?
I see that Chipotle Grill has chosen Nation Taco Day* to announce an exciting “new” addition to their menu–chorizo. Like everyone south of the Riviere Rouge hasn’t been eating chorizo and egg breakfast tacos since the Eisenhower Lincoln Administration. Still, what can you expect from America’s innovator in digestive surprises, when they have a suppository** Read more
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Safe Spaces
Seems like every WLB in Christendom wants a “safe space” these days. The rich and stupid are doing it with luxury bunkers, while a Texas chapter of the Sons of Martha are taking a more proactive approach. Tips from American Digest and Happy Acres. Appropo of nothing, I’m reminded of this bit of bunker lore: Read more
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R Tutorial: A Bayesian Estimate of Proportion
This is an old chestnut in Bayesian statistics, using the conjugate beta prior to find a beta posterior distribution for a proportion. If you’re unfamiliar with the calculation of the posterior distribution, there’s a link in the tutorial. Read more
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R Tutorial: Teasing Out a Markov Chain
Azzalini and Bowman’s Old Faithful geyser data provides fodder for a lot of data exploration in R (scatterplots, ggplot2, simple regression, kmeans clustering, and Markov chain estimation). All the really interesting stuff in the tutorial happens if you click through to Analysis > Models > Standardized Cluster Model. (The standardized clustering approach is not given Read more
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Beginning: R Tutorials
After a long, slow start, R is catching on with statisticians and (some) scientists at UTSA. The Biology Department has asked that I use R in teaching biostatistics, and many of the courses for statistics majors are using R rather than SAS (a UTSA tradition). Students have not been idle; the statistics club has asked Read more
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The Invention of Nature
I’m neck deep in Andrea Wulf‘s biography of Alexander von Humboldt, and it’s absolutely riveting. Von Humboldt was some kind of scientific maniac, who caught the interest of everyone from Goethe to Thomas Jefferson to Simon Bolivar. Von Humboldt was arguably the first naturalist to think ecologically, as well as one of the earliest abolitionists. Read more
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Guys Crush Math SAT
No ability differences between men and women? Then what’s up with this? Read more
The Random Texan 