[R] is an excellent open-source statistics language. It's cross-platform and free and I think it will eventually displace proprietary stat's packages due to its rapid development, speed and ease of use. So there's no time like the present to get used... [Read more...]

One of my favorite R packages that I use all the time is the RColorBrewer package. The package has been around for a while now and is written/maintained by Erich Neuwirth. The guts of the package are based on Cynthia Brewer’s very cool work on the us... [Read more...]

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Note: This post is NOT financial advice!  This is just a fun way to explore some of the capabilities R has for importing and manipulating data.   In a previous post, I examined a simple stock trading strategy: Find the high point over the la... [Read more...]

Nodes are used in tikz to place content in a picture as part of a LaTeX document. Fast Tube by Casper When creating a tikz picture the origin is assumed to be at (0,0) and objects are placed with positioning relative to the origin on the picture. If we wanted to ... [Read more...]

So, installing rgdal, which is an important R package for spatial data analysis can be a bit of a pain on the mac. Here are two ways to make it happen.   The Easy Way In R run: install.packages('rgdal',repos="http://www.stats.ox.ac.uk/pub/RWin") The ... [Read more...]

  The sqldf package can be used to run sql queries on R data frames. The user simply needs to specify a sql statement enclosed by quotation marks within the sqldf() function. In the follow R code, you see various ways of using the sqldf package to run sql queries on ... [Read more...]

I found this great R-Visualization example via an R-Blogger post that xingmowang made. (One more good reason for why it is important to read lots of field-related blogs!)Here's the image:If this was merely eye-candy, I would have enjoyed it, but not in... [Read more...]

A substantial part of my job has little to do with statistics; nevertheless, a large proportion of the statistical side of things relates to applications of linear mixed models. The bulk of my use of mixed models relates to the … Continue reading → [Read more...]

As an ameturer programmer (one without proper trainings in any mainstream programming language — C and Java) , the more I use R the more I understand the saying — “You are only bounded by your imagination”. The other day I … Continue reading → [Read more...]

Update to my pscl package, now on CRAN. Biggest change: fixing a bug in the way MCMC draws for item parameters were being stored and summarized by ideal. [Read more...]

During a short if profitable visit to Dublin for a SFI meeting on Tuesday/Friday, I had the opportunity to visit the National Gallery of Ireland in my sole hour of free time (as my classy hotel was very close). The building itself is quite nice, being well-inserted between brick ... [Read more...]

In this post, Portfolio Probe explores a way to decide whether market kurtosis and skewness are predictable. Market skewness, in naive financial modeling, is some kind of measure of (as-)symmetrical distribution of (daily) returns around the average market return. A higher skewness would tend to indicate a denser distribution ... [Read more...]

Once you’re comfortable with 2-arrays and 2-matrices, you can move up a dimension or two, to 4-arrays or 4-tensors. You can move up to a 3-array / 3-tensor just by imagining a matrix which “extends back into the blackboard”. Like a 5 × 5 ma... [Read more...]

While working for my Financial economics project I came across this elegant tool called Principal component analysis (PCA)which is an extremely powerful tool when it comes to reducing the dimentionality of a data set comprising of highly correlated var... [Read more...]

Since we explored some statitics of an abstract painting with Pierre (we even have an article in Variances last issue!), I became more sensitive to art linked to randomness. Here are some pointers to related websites I have digged out. Random.org, mentioned here by Pierre, is, at it reads, ... [Read more...]

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During construction of typical efficient frontier, risk is usually measured by the standard deviation of the portfolio’s return. Maximum Loss and Mean-Absolute Deviation are alternative measures of risk that I will use to construct efficient frontier. I will use methods presented in Comparative Analysis of Linear Portfolio Rebalancing Strategies: ... [Read more...]

One of the more interesting things I have come across is the idea of looking at price changes in terms of recent standard deviation, a concept put forward by Jeff Augen. The gist is to express a close to close return as a function of the standard devia... [Read more...]

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