If you are creating maps then for goodness sake Use sensible colours!  I was helping some undergraduates with some work the other day, and they decided to use the following colour scheme for representing river depth: Deep water: Red Medium-depth water: Bright green Shallow water: Pink Why did they do ... [Read more...]

In view of open-source parallel computing with R this week presents a big step to the future. R 2.14.0 was released at October 31th, 2011. Now, R base ships with a parallel computing package called “parallel”.  library(parallel) It combines advantages of the packages multicore and snow and it contains support for ... [Read more...]

The Gaussian vector is extremely interesting since it remains Gaussian when conditioning. More precisely, if is a Gaussian random vector, then the conditional distribution of is also Gaussian. Further, it is possible to derive explicitly the cova... [Read more...]

Thanks to everyone for participating in the "Applications of R in Business" contest. R users submitted more than 25 entries, describing how R is used in industries including life sciences, finance, manufacturing, sentiment analysis, and even sports. Some entries are just outlines for now (competitors have until November 30 to finalize their ... [Read more...]

Recently, I've been preparing a poster using the LaTeX packages Beamer and beamerposter. The poster discusses a bunch of R stuff that I've been doing lately, so I successfully used Sweave to incorporate R code into the poster. However, I had some troub... [Read more...]

For this years Halloween I presented the mathematical biology seminar at the Centre for Mathematical Biology. Here is the title and the abstract… Cycles in finite populations: a reproducible seminar in three acts Many natural populations exhibit cyclic fluctuations. Explaining the underlying … Continue reading → [Read more...]

Paid search marketing refers to the process of driving traffic to a website by purchasing ads on search engines. Advertisers bid on certain keywords that users might search for, and that determines when and where their ads appear. For example, an individual who owns an auto dealership would want to ... [Read more...]

As supplementary material to the ABC paper we just arXived, here is the R code I used to produce the Bayes factor comparisons between summary statistics in the normal versus Laplace example. (Warning: running the R code takes a while!) Filed under: R, Statistics, University life Tagged: ABC, Bayesian model ... [Read more...]

You may often use "Beta" to measure the market exposure of your portfolio because it's easy to calculate.Since I have been wondering how much "Beta" change depending on time, more precisely writing, data-set and the period of return time series, I... [Read more...]

One additional new feature in the latest release of R: the standard binaries of R 2.14 from the R Project now include Cairo support. For Windows users, this means that you can now create SVG graphics in R -- the best format for displaying R graphics on the web -- without ... [Read more...]

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Sure thing….this is just the sort of thing for which rOpenSci is being built. A colleague of mine recently saw our packages in development and thought, “Hey, that could totally make my life easier.”   What was made easier you ask?   This was his situation: He had a list of ... [Read more...]

My article on computing on the language was unexpectedly popular and so I wanted to quickly follow up on my own solution. Many of you got the answer, and in fact many got solutions that were quite a bit shorter than mine. Here’s how I did it: makeList [Read more...]

I bought an Android phone, nothing fancy just my first foray in the smartphone world, which is a big change coming from the dumb phone world(*). Everything is different and I am back at being a newbie; this is what … Continue reading → [Read more...]

Bootstrapping a Single Statistic (k=1) The following example generates the bootstrapped 95% confidence interval for R-squared in the linear regression of miles per gallon (mpg) on car weight (wt) and displacement (disp). The data source is mtcars. The... [Read more...]

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In the Maximum Loss and Mean-Absolute Deviation risk measures, and Expected shortfall (CVaR) and Conditional Drawdown at Risk (CDaR) posts I started the discussion about alternative risk measures we can use to construct efficient frontier. Another alternative risk measure I want to discuss is Downside Risk. In the traditional mean-variance ... [Read more...]

If part of the role of data journalism is to make transparent the justification behind claims that are, or aren’t, backed up by data, there’s good reason to suppose that the journalists should be able to back up their own data-based claims with evidence about how they made ... [Read more...]

Line Plots (Econometric in R) Input: ## ---------------------------- ## ## Plotting Points *and* Lines ## ## ---------------------------- ## pow = c(0.95, 0.6, 0.3, 0.15, 0.1, 0.05, 0.1, 0.15, 0.3, 0.6, 0.95) pow2 = c(0.99, 0.75, 0.4, 0.2, 0.15, 0.0... [Read more...]

Sometimes people ask very basic questions on the R-help mailing list, which could have easily been answered by reading some R manual or doing a quick Google search. Responses on the mailing range from people answering the question to “Please… See more › [Read more...]