(Update) Despite the original publish date (Apr 1), this post was not and April Fools joke. I’ve also shortened the title a bit. As part of my job, I develop utility applications that automate workflows that apply more involved analysis algorithms. When feasible, I deploy web applications as it lowers ... [Read more...]

In a previous post on my personal blog about creating Pivot Tables in R with melt and cast we covered a simple way to generate sales reports and summary tables from a data set consisting of orders. It is often said that a picture is … Continue reading → [Read more...]

About 3 years ago I published some code on this blog to draw a Kaplan-Meier plot using ggplot2. Since then, ggplot2 has been updated (from 0.8.9 to 0.9.3.1) and has changed syntactically. Since that post, I have also become comfortable with Git and Github. I have updated the code, edited it for a ... [Read more...]

When introducing copulas, it is commonly admitted that copulas are interesting because they allow to model the marginals and the dependence structure separately. The motivation is probably Sklar’s theorem, which says that given some marginal cumulative distribution functions (say  and , in dimension 2), and a copula (denoted ), then we can ... [Read more...]

When you take a photograph, you can include the date in the image, so you remember when you created it.  (In fact, under EXIF format, it’s stored in the image file anyway, even if it doesn’t appear in the picture.)  Wouldn’t it be nice to make annotations ... [Read more...]

Hello all of you Stata loving statistical analysts out there!  I have great news.  I am finally nearly done with the package I have been working on which provides the mechanism for Stata users to seamlessly move from Stata to R though use of ... [Read more...]

During a lunchtime discussion among recent GCaP class attendees, the topic of weather came up and I casually mentioned that the weather in Melbourne, Australia, can be very changeable because the continent is so old that there is very little geographical relief to moderate the prevailing winds coming from the ... [Read more...]

I had no intention to blog this, but @jayjacobs convinced me otherwise. I was curious about the recent (end of March, 2014) California earthquake “storm” and did a quick plot for “fun” and personal use using ggmap/ggplot. I used data from the Southern California Earthquake Center (that I cleaned up ... [Read more...]

R is a statistical analysis package based on writing short scripts or programs (versus being based on GUIs like spreadsheets or directed workflow editors). I say “writing short scripts” because R’s programming language (itself called S) is a bit of an oddity that you really wouldn’t be using ... [Read more...]

by Seth Mottaghinejad, Analytic Consultant for Revolution Analytics You may have heard before that R is a vectorized language, but what do we mean by that? One way to read that is to say that many functions in R can operate efficiently on vectors (in addition to singletons). Here are ... [Read more...]

Facts do not speak (Henry Poincare) Mr. Penney is my best friend. He is maths teacher and loves playing. Yesterday we were in his office at the university when he suggested me a game: When you toss a coin three times, you can obtain eight different sequences of tails and ... [Read more...]

In econometrics, generalized method of moments (GMM) is one estimation methodology that can be used to calculate instrumental variable (IV) estimates. Performing this calculation in R, for a linear IV model, is trivial. One simply uses the gmm() function in the excellent gmm package like an lm() or ivreg() function. ... [Read more...]

In graph theory (and its applications) it is often required to model how information spreads within a given graph. This is interesting for many applications, such as attack prediction, sybil detection, and recommender systems - just to name a... [Read more...]

Does the transition to and from Daylight Saving Time (DST) have a (significant) effect on the stock market? In a recent blog post on The UK Stock Market Almanac, the author found that the average return of the FTSE100 index for the days following the start of British Summer Time (... [Read more...]

Here’s a post that appears on my new website, ragscripts.com. On-line resources for analysts are often either too general to be of practical use or too specialised to be accessible. The aim of ragscripts.com is to remedy this by providing start to finish directions for complex analytical ... [Read more...]

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