Using data from the INEGI I calculated the percentage of births who were born outside of marriage in Mexico and compared it to the Hispanic rate in the US. They are basically the same. There’s been a gigantic increase that’s slouching towards 50% a... [Read more...]

Over the next few posts, I’m going to be reviewing the use of R to implement the most commonly used matrix techniques for image manipulation. The code will be surprisingly simple to understand, because the real magic behind these techniques lies in the mathematics that R provides an abstract ... [Read more...]

Lately, I’ve been running a series of fMRI experiments on visual perception. In the interests of understanding the underlying properties of the images I’m using as stimuli, I’ve been trying to learn more about the matrix transformations commonly used for image compression and image manipulation. Thankfully, R ... [Read more...]

An important aspect of regression involves assessing the tenability of the assumptions upon which its analyses are based. This tutorial will explore how R can help one scrutinize the regression assumptions of a model via its residuals plot, normality h... [Read more...]

With a little guidance from the indefatigable Hadley Wickham, I figured out today how to implement the setter methods that were missing from my example user class. To review, let’s rebuild the getter methods for my user object: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 [...] [Read more...]

The New York Times last weekend looked at the controversy around the recent changes to the mammogram guidelines from a mathematical perspective. Compared to the analysis based on Bayes' Theorem from the Harvard Social Science Statistics blog (which apparently caused some controversy itself: that post was deleted and later replaced ... [Read more...]

IowaHawk has a excellent article attempting to reproduce the infamous CRU climate graph using OpenOffice: Fables of the Reconstruction. We thought we would show how to produced similarly bad results using R. If the re-constructed technique is close to what was originally done then so many bad moves were taken ... [Read more...]

Until recently, I’ve never had any reason to learn how to define my own classes in R. Having learned this week, I was surprised to find out how easy it is to start implementing classes in R. If you know nothing about creating classes and class methods in R, ... [Read more...]

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Let’s say that you’re fitting a cumbersome model so time is not to waste over a PC staring at the screen half anxious-half bored… Then, you can always leave and go on with meetings and all your daily routine and have R notify you the results! How? We ... [Read more...]

I’m a little surprised by Andrew Gelman’s post today, doubting the wisdom of a passage from Gary Becker’s work that reads: According to the economic approach, therefore, most (if not all!) deaths are to some extent “suicides” in the sense that they could have been postponed if ... [Read more...]

This term, I’ve been sitting in on Rene Carmona’s course on Modern Regression and Time Series Analysis. Much of the material on regression covered in the course was familiar to me already, but I’ve never felt that I had a real command of times series analysis methods. ... [Read more...]

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Since people have asked, here is a GitHub page with all of the code used to generate my R function usage analyses: cran-function-usage-analysis. [Read more...]

This morning, I got a chance to read enough of the R Language Definition to finish my implementations of push and pop. While I was at it, I also wrote implementations of unshift, shift, queue and dequeue. Here they are: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 push [Read more...]

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Yesterday, Hadley Wickham commented on my post on the frequency of calling various R functions that it would be helpful to have the number of packages that call a function in addition to the number of times that the function is called. I compiled the relevant data last night: you ... [Read more...]

Having grown up with Perl, there are two functions that I desperately miss while programming in R: push and pop. Continually writing 1 vector [Read more...]

End of semester madness has begun, so posting will likely be light this week. To keep you busy, David Lazer recently posted the five video series of the Goudreau-Hunter tutorial on social network analysis using R from the 2009 Harvard Political Networks Conference. Each video run about 60 minutes, so these will ... [Read more...]