Unison graph and parallel coordinate graph share similar thought in visualising the difference of multidimensional data, thought the former is much more complicated. Based on iris data, we can see their performance.Parallel coordinate graphAndrews' Cur... [Read more...]

There are many types of scatterplots in R, here are some examples based on the famous Iris data.pairs() and coplot() in package graphics.gpairs() in package YaleToolkit.scatterplot.matrix() or spm() in package car.splom() in package lattice. [Read more...]

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While so-called “between-subjects” ANOVA is absolutely straightforward in R, performing repeated measures (within-subjects) ANOVA is not so obvious. I have come across at least three different ways of performing repeated measures ANOVA in R. Which method you use depends on … Continue reading → [Read more...]

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A few days ago I was reading an article by Jean Drèze and his colleagues on how the first two years of National Rural Employment Guarantee Act (NREGA) has progressed (There was another article by Drèze on NREGA in 2007). The NREGA is empowering the rural people in a ... [Read more...]

A week ago, Amma was telling the weather was getting hot in Coimbatore. I was telling her it is going to get worse in the next two months. She shot back saying that March is the hottest month while April and May are less hotter in Coimbatore. Growing up in ... [Read more...]

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Hey all of you,I got such an interesting problem, a friend of mine is modelling something using bayesian statistics and she got an equation system to solve, but she's stucked and she showed to me such a long script to ty to solve it with numeric approx... [Read more...]

Well... I don’t really know what to write, but Iknow that I want to say ‘Welcome’ to all of you who are checking this blog, I’m a student, majoring in Actuarial Science in Mexico city, and I thought about a place where we could share ideas and knowledge ... [Read more...]

This is why I love XKCD, though surely the best part of this strip was the mouseover: “correlation doesn’t imply causation, but it does waggle its eyebrows suggestively and gesture furtively while mouthing, ‘look over there’.” [Read more...]

I seem to be doing more and more with Python for work over and above using it as a generic scripting language. R has been my workhorse for analysis for a long time (15+ years in various incarnations of S+ and R), but it still has some deficiencies. I’m finding ... [Read more...]

Adam Gehr of DePaul University's Finance Department had organized a panel session about R in Finance at the Midwest Finance Association's 58th Annual Meeting which is happening this week here in Chicago. I just posted my slides on my presentations page. The slides give a brief overview of R, the ... [Read more...]

We Americans have a reputation as being unworldly. Given the results of the most recent Pew survey, perhaps we deserve it. Evidently, the majority of us never move out of our home states. [Read more...]

Being a drummer, a programmer and a fan of statistical analysis, this post on the (unnaturally) perfect timing of drum parts recorded to a click track was a real delight to me. Of course, many claims in the post are odd: it seems hard to imagine that a... [Read more...]

The changes in Rcpp that I blogged about a few days ago required a few small changes in RQuantLib. Not really much more that prefixing std:: in a number of variable declarations and a few member function calls -- so this is definitely a minor maintenance release. New source and ... [Read more...]

I got an email, asking me if our arm package can simulate tobit model to get simulated parameters. Indeed, arm does not suport tobit model. It only support sim() for lm, glm and mer classes in R. But it is not difficult to get a tobit verison of sim(). Here ... [Read more...]

A recurrent source of irritation for me is the absence of a good default behavior in R for choosing the color scheme for bar plots. A stacked bar plot looks only as good as the color scheme you use. In hope of finding a usable scheme that I could settl... [Read more...]

THE VALUE OF NOT FOLLOWING INSTRUCTIONS As Shane Frederick has noted, if you say “A bat and a ball cost $1.10. The bat costs $1 more than the ball. How much is the ball?”, you will notice that the vast majority of your friends will say “10 cents” instead of the correct “5 cents”, ... [Read more...]

A new maintenance version of Rcpp (now at 0.6.4) was just pushed to CRAN and has been uploaded to Debian. Rcpp is a set of utility classes that provide interfaces for transferring the major R data types to C++ and back which makes it easier to extend R with dynamically loadable ... [Read more...]