Visualizing Climbing Ropes

October 3, 2011
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Visualizing Climbing Ropes

Today’s market of climbing ropes offers a huge variety of models to choose from. If you don’t have a good idea of what you want, the task of selecting a rope can become a true challenge, or worst, almost a … Continue reading →

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The four steps to publication-grade graphics in R

October 3, 2011
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This Article is also available in EN, ES.

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OLS beta VS. Robust beta

October 3, 2011
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OLS beta VS. Robust beta

In financial context, is suppose to reflect the relation between a stock and the general market. A broad based index such as the S&P 500 is often taken as proxy for the general market. The , without getting into too … Continue reading →

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Twitter updates on R Graph Gallery

October 3, 2011
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Twitter updates on R Graph Gallery

I've added a twitter search widget that searches for the #rgraphgallery hashtag or the url of the gallery on the front page.

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Predictability of kurtosis and skewness in S&P constituents

October 3, 2011
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Predictability of kurtosis and skewness in S&P constituents

How much predictability is there for these higher moments? Data The data consist of daily returns from the start of 2007 through mid 2011 for almost all of the S&P 500 constituents. Estimates were made over each half year of data.  Hence there are 8 pairs of estimates where one estimate immediately follows the other. … Continue reading...

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Model Exploration using K-sample Plot in Big Data

October 3, 2011
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Model Exploration using K-sample Plot in Big Data

Generically, error rate of predicting binary variable by a certain model becomes plateau increasing sample size. When the model fits training data , the error rate gains from 0 to true error. And when the model fits test data, the error rate decreases ...

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Visual Illusions: Google vs Facebook vs Yahoo

October 3, 2011
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Visual Illusions: Google vs Facebook vs Yahoo

The ability to visualize data, enabled by the advent of graphical computer tools, has been a great boon to Cap and Perf. The power derives from the way graphical displays provide an efficient impedance match to the visual system in our brain. The weakness derives from the way graphical displays provide an efficient impedance match to the visual system...

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Jeff Augen Volatility Spike Code in R

October 2, 2011
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Jeff Augen Volatility Spike Code in R

Jeff Augen has written many excellent books on options trading, including&nb...

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Adding a volatility filter with VIX

October 2, 2011
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Adding a volatility filter with VIX

We saw in the basic system how we could add a factor, namely the 200 day moving average, to improve the overall performance of our system. You could spend a lot of time playing with different moving averages, and different combinations of crossovers if...

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vectorplot in rasterVis

October 2, 2011
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vectorplot in rasterVis

The function slopeAspect from raster provides the vector field (gradient) from a scalar field stored in a RasterLayer object. The magnitude (slope) and direction (aspect) of the vector field is usually displayed with a set of arrows (e.g. quiver in Matlab). rasterVis includes now a method, vectorplot, to calculate and display this vector field

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Modelling with R: part 2

October 2, 2011
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Modelling with R: part 2

I apologize for the delay in the second post (just in case anybody was waiting), I had been vary involved with work the past week. I shall try to be more regular. Well, in the previous post, we successfully imported data into R and got a basic "feel" o...

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Latent class mixed models – with graphics

October 2, 2011
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Latent class mixed models – with graphics

Foreword Apologies that the output isn’t showing well as far as spacing and alignment is concerned. Am working on fixing that! Background Generally when we have a set of data, we have known groupings. Be that three different treatment groups, … Continue reading →

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Let R fly: Visualizing Export Data using R

October 2, 2011
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Let R fly: Visualizing Export Data using R

Having been using R for 5+ years, visiting www.r-bloggers.com daily, learning cool tricks from it and knowing cool UseRs from it, I finally decide to quit being an observer and start to be a contributor to this wonderful community. In this very … Continue reading →

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Overhead cost of a function call

October 1, 2011
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Overhead cost of a function call

Recently, I would like to apply unit testing method to my R program. The first thing i need to chop every few lines of the code into functions so that I can test each of them. A Question comes up to my mind: What is the overhead cost of a function call? To answer this

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Updated examples that combine Rcpp and CppBugs

October 1, 2011
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This example is very informative in illustrating how to use CppBugs module with Rcpp to conduct fast MCMC simulation in R.

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Reminder: One week til Rcpp class in San Francisco

October 1, 2011
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Just a quick note to remind everyone that the Rcpp class in San Francisco, which I am holding together with Revolution Analytics, will take place a week from today. We are happy to report that the number of registrations has met our initial target...

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Dollars and cents: How are you at estimating the total bill?

September 30, 2011
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Dollars and cents: How are you at estimating the total bill?

When estimating the cost of a bunch of purchases, a useful heuristic is rounding to the nearest dollar. (In fact, on US income tax returns, one is allowed to omit the cents). If prices were uniformly distributed, the following two heuristics would be equally accurate: * Rounding each item up or down to the nearest dollar and summing * Rounding each...

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R Graph Gallery – Donations Welcome

September 30, 2011
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R Graph Gallery – Donations Welcome

I've added a PayPal button into the graph, just in case people want to help the development of the website

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Difficult Month for One of My Best Ideas

September 30, 2011
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Difficult Month for One of My Best Ideas

THIS IS NOT INVESTMENT ADVICE.  MY IDEAS PROBABLY WILL LOSE YOU MONEY, AND I WILL NOT LET YOU KNOW WHEN I CHANGE MY MIND. Bloomberg’s article “Asian Currencies Set for Worst Month Since 1997 Crisis Caused IMF Bailouts” demonstrates why with ...

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ttrTests This is a Test Test 3:Data Snoopy

September 30, 2011
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ttrTests This is a Test Test 3:Data Snoopy

THIS IS NOT INVESTMENT ADVICE.  IT IS JUST AN EXAMPLE AND WILL LIKELY LOSE LOTS OF MONEY IF YOU PURSUE WHAT IS DISCUSSED.  READER IS RESPONSIBLE FOR THEIR OWN GAINS OR LOSSES.  IF YOU ARE AN UNLIKELY WINNER, I WOULD LOVE TO HEAR YOUR STO...

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R tutorial on visualizations/graphics

September 30, 2011
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R tutorial on visualizations/graphics

Rolf Lohaus, a Huxley postdoctoral fellow here in the EEB dept at Rice University, gave our R course a talk on basic visualizations in R this morning.Enjoy!

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R 2.13.2 released

September 30, 2011
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The R core team announced today that R 2.13.2 is now available: The byte pixies have rolled up R-2.13.2.tar.gz at 9:00 this morning. This is intended to be the final release of the 2.13 series, for the benefit of those apprehensive of putting 2.14.x into production use. This update fixes a number of minor bugs (for example, pch="." will...

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Rcpp 0.9.7

September 30, 2011
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A fresh maintenance release version 0.9.7 of Rcpp went onto CRAN and into Debian earlier today. This release contains two contributed fixes. The first, suggested by Darren Cook via the rcpp-devel mailing list, corrects how we had set up excepti...

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Microfinance Map of India – another go…

September 30, 2011
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Microfinance Map of India – another go…

I gave it another go, trying to get a map that looks a bit nicer. This time, I tried to compute something like a density or intensity in a certain area. On the previous map, this was not visible very well. I used ggplot2 and a bit of R code, together with RGoogleMaps to produce the

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Monitoring Productivity II – the Others

September 30, 2011
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Monitoring Productivity II – the Others

In previous Monitoring Productivity Experiment post I looked into the hours I spent in computer, now will look into the hours Others spend in computer, which is far more interesting :) To find things like what day people spend more time on computer, ho...

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Setting the initial view of a motion chart in R

September 30, 2011
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Setting the initial view of a motion chart in R

Following on from my article about accessing and plotting World Bank data with R I want to talk about how to change the initial view of a motion chart.Over the last couple of weeks I have been asked a view times how to do this. For instance Stephen O'G...

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Customizing your .rprofile

September 29, 2011
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I searched around to see if there was a blog post somewhere describing how to customize one’s .rprofile but was surprised to find just one outdated post. So here is quick intro on the topic. If you are a power R user, you already know about what it does. For those of you that don’t,

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Modelling with R: part 1

September 29, 2011
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Modelling with R: part 1

When I started work about 3 months ago, I didn't know much more than loading data and executing standard Econometric commands in R. But now I feel much much much more confident in using R for work, for research, for puzzles, and sometimes just for fun....

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Obama 2012 campaigning with analytics

September 29, 2011
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The campaign to re-elect US president Barack Obama is hiring -- and the RDataMining blog noticed that several of the open positions seek R skills. If you want to be a Communications Analyst, Digital Strategy Analyst, or Statistical Modeling Analyst and you know R, there may be a job opening for you. Just goes to show there's no corner...

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