A Bernoulli process is a sequence of Bernoulli trials (the realization of n binary random variables), taking two values (0/1, Heads/Tails, Boy/Girl, etc…). It is often used in teaching introductory probability/statistics classes about the binomial distribution. When visualizing a Bernoulli process, it is common to use a binary ... [Read more...]

The subset function is available in base R and can be used to return subsets of a vector, martix, or data frame which meet a particular condition. In my three years of using R, I have repeatedly used the subset() function and believe that it is the most useful tool ... [Read more...]

What is important for an investor? The rate of return is at the top of the list. Does the expected rate of return shown on the mean-variance efficient frontier paints the full picture? If investor’s investment horizon is longer than one period, for example 5 years, than the true measure ... [Read more...]

Many high-schoolers are now using R in class, and to help even more students get exposure to R (while improving R itself), Virgilio Gómez-Rubio is seeking suggestions for projects for the next Google Code-In: An application has been put forward for R to participate in Google Code-in. This is ... [Read more...]

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Earlier today, I saw a post vis the aggregating R-Bloggers service a post on Using Text Mining to Find Out What @RDataMining Tweets are About. The post provides a walktrhough of how to grab tweets into an R session using the twitteR library, and then do some text mining on ... [Read more...]

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CloudStat: Learn & Do R on the Cloud CloudStat is a platform to learn and do R on the Cloud. With CloudStat, there is no more download, installation, update and maintenance. CloudStat decrease the R language learning curve besides collaboration. And it... [Read more...]

The arithmetic sequence, 1487, 4817, 8147, in which each of the terms increases by 3330, is unusual in two ways: (i) each of the three terms are prime, and, (ii) each of the 4-digit numbers are permutations of one another. There are no arithmetic sequences made up of three 1-, 2-, or 3-digit primes, ... [Read more...]

Dataspora recently analyzed Lending Club‘s data in a geographical way using the data distributed by the site. Lending Club is an online financial community that brings together creditworthy borrowers and savvy investors so that both can benefit financially. We replace the high cost and complexity of bank lending with ... [Read more...]

This is a followup to a post I uploaded earlier today about web scraping data off Google Scholar. In that post I was frustrated because I’m not smart enough to use xpathSApply to get the kind of results I wanted. However fast-forward to the evening whilst having dinner with ... [Read more...]

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Avril Coghlan, a lecturer at University College Cork in Ireland, has written and made available for free three books ideal for students or practitioners new to R who want to use it for multivariate analysis, time series analysis or biomedical statistics. Each book begins with practical advice for installing and ... [Read more...]

I do reports for clients with LyX and Sweave. It took me an extremely long time to get them working, but now that they’re working I can do more in an hour and thus charge more per hour. If you’re not familiar, here’s a rundown: LaTeX is ... [Read more...]

This post shows an example on text mining of Twitter data with R packages twitteR, tm and wordcloud. Package twitteR provides access to Twitter data, tm provides functions for text mining, and wordcloud visualizes the result with a word cloud. … Continue reading → [Read more...]

I created an R package to read grads data. As far as I know, there is no dedicated package to read grads data. The package is still quite new, any remarks on the documentation or code are more than welcome.… See more › [Read more...]

Setting up AWS Cluster I wanted to setup an AWS cluster to take a shot at a Kaggle contest – DunnHumby Challenge http://www.kaggle.com/c/dunnhumbychallenge For this, I found StarCluster to be of great help. It allows you to set-up AWS nodes in a few lines of code ... [Read more...]

I wanted to scrape the information returned by a Google Scholar web search into an R data frame as a quick XPath exercise. The following will successfully extract  the ‘title’, ‘url’ , ‘publication’ and ‘description’.  If any of these fields are not available, as in the case of a citation, the ... [Read more...]

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The erstwhile big 4 all blanked their opponents last Saturday and a poster on the Guardian wondered when was the previous occasion of such an occurrence. It’s a pretty simple procedure in SQL using a subquery, but in the spirit of learning R, I thought I would tackle the problem ... [Read more...]