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Le Monde puzzle [#743]

October 11, 2011
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Le Monde puzzle [#743]

As Le Monde weekend has yet again changed its format (with so much more advertisements for luxurious items that I sometimes wonder whether or not this is the weekend edition of Le Monde!], it took me a while to locate the mathematical puzzle. The good news is there now is a science&techno leaflet with, at

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understanding computational Bayesian statistics

October 9, 2011
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understanding computational Bayesian statistics

I have just finished reading this book by Bill Bolstad (University of Waikato, New Zealand) which a previous ‘Og post pointed out when it appeared, shortly after our Introducing Monte Carlo Methods with R. My family commented that the cover was nicer than those of my own books, which is true. Before I launch into

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Risk, Return and Analyst Ratings

October 7, 2011
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Risk, Return and Analyst Ratings

Today I want to discuss a connection between Risk, Return and Analyst Ratings. Let’s start with defining our universe of stocks : 30 stocks from Dow Jones Industrial Average (^DJI) index. For each stock I will compute the number of Upgrades and Downgrades, Risk, and Return in 2010:2011. I will run a linear regression and

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In case you missed it: September Roundup

October 7, 2011
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In case you missed them, here are some articles from September of particular interest to R users. The deadline to enter the "R Applications" contest with $20,000 in prizes is October 31. The RHadoop Project, a new collection of open-source R packages from Revolution Analytics, makes it possible to write map-reduce jobs in R to analyze huge data sets...

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Visualizing Tables with plot.table

October 6, 2011
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Visualizing Tables with plot.table

plot.table function in the Systematic Investor Toolbox is a flexible table drawing routine. plot.table has a simple interface and takes following parameters: plot.matrix – matrix with data you want to plot smain – text to draw in (top, left) cell; default value is blank string highlight – Either TRUE/FALSE to indicate if you want to

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Assumptions of the Linear Model

October 6, 2011
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Assumptions of the Linear Model

Linear Assumptions from the Analysis Factor – Assumptions of linear regression (and ANOVA) are about the residuals, not the normality or independence of the response variable (Y). If you don’t know what this means be sure to read this brief … Continue reading →

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Do cents follow Benford’s Law?

October 5, 2011
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Do cents follow Benford’s Law?

Benford's law is an amazing thing. If you know the probability distribution that classes of "natural" numbers should have, you can detect where people might be faking data: phony tax returns, bogus scientific studies, etc.

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Calling Google Maps API from R

October 5, 2011
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Calling Google Maps API from R

Hi, Related to Julyan’s previous post, I want to share an easy way to access Google Maps API through R. And then we’ll stop about Google, otherwise it’ll look like we’re just looking for jobs. My problem was the following: … Continue reading →

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Interactive charts with googleVis package and R

October 4, 2011
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Interactive charts with googleVis package and R

Examples at the link below illustrate interactive charts created with the googleVis package and R. http://code.google.com/p/google-motion-charts-with-r/wiki/GadgetExamples Some amazing features are: a motion chart shows the changes over time, an AnnotatedTimeLine shows zoom-in/zoom-out view of time series, a TreeMap supports drill-down … Continue reading →

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Introduction to PloTA library in the Systematic Investor Toolbox

October 4, 2011
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Introduction to PloTA library in the Systematic Investor Toolbox

PloTA ( plot + ta ) library in the Systematic Investor Toolbox is a simple plot interface to charting Time Series and Technical Analysis plots. I created it as an alternative to charting functionality in quantmod package. It is designed to mimic default plot interface and works with xts objects. PloTA implements following methods: plota

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