Monthly Archives: October 2012

Why pictures are so important when modeling data?

October 31, 2012
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Why pictures are so important when modeling data?

(bis repetita) Consider the following regression summary,Call: lm(formula = y1 ~ x1)   Coefficients: Estimate Std. Error t value Pr(>|t|) (Intercept) 3.0001 1.1247 2.667 0.02573 * x1 0.5001 0.1179 4.241 0.00217 **...

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Regime Detection

October 31, 2012
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Regime Detection

Regime Detection comes handy when you are trying to decide which strategy to deploy. For example there are periods (regimes) when Trend Following strategies work better and there are periods when Mean Reversion strategies work better. Today I want to show you one way to detect market Regimes. To detect market Regimes, I will fit

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More data apps spawned by Sandy

October 31, 2012
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More data apps spawned by Sandy

As the clean-up continues on the eastern seaboard, I wanted to follow up on Monday's post on tracking Hurricane Sandy with Open Data with a couple of other R-based data applications spawned by the storm. Josef Fruehwald created an R script to tap into local weather sensors to keep track of air pressure, wind speed and rainfall near his...

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draw figures in CMYK mode in R

October 31, 2012
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draw figures in CMYK mode in R

Print publication usually ask to use CMYK (instead of RGB) color mode for figures (because not every color can be print out), while we usually use RGB for screen reading (because screen has larger range of color scale). Of course we can convert RGB to ...

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Using R with Routino to provide road network paths between random Tweets and an iconic Smiths landmark

October 31, 2012
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Using R with Routino to provide road network paths between random Tweets and an iconic Smiths landmark

A couple of days ago I posted how you can go about installing Routino on OSX; and now I have just finished writing a quick post over on my Rpubs blog about how you go about using it from within R. I also wanted to know a bit more about how R and Twitter play

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Hierarchical linear models and lmer

October 31, 2012
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Hierarchical linear models and lmer

Hierarchical linear models and lmer Article by Ben Ogorek Graphics by Bob Forrest Background My last article featured linear models with random slopes. For estimation and prediction, we used the lmer function from the lme4 package. Today we'll consider another level in the hierarchy, one...

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GGtutorial: Day 3 – Introduction to Colors

October 31, 2012
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GGtutorial: Day 3 – Introduction to Colors

So, where does ggplot get its colors? If you’ve ever asked ggplot to color on the basis of a factor, you might have beeen surprised by the default color choices.  The fact is, ggplot colors factors on the basis of finding evenly spaced colors a...

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Using R with Routino to provide road network paths between random Tweets and an iconic Smiths landmark

October 31, 2012
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A couple of days ago I posted how you can go about installing Routino on OSX; and now I have just finished writing a quick post over on my Rpubs blog about how you go about using it from within R. I also wanted to know a bit more about how R and Twitte...

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Fitting Distributions to Data with R

October 31, 2012
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In “Fitting Distributions with R” Vito Ricci writes;“Fitting distributions consists in finding a mathematical function which represents in a good way a statistical variable. A statistician often is facing with this problem: he has some observations of a quantitative character and he wishes to test if those observations, being a sample of an unknown population, belong from a...

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Edmonton R User Group is going live

October 30, 2012
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Edmonton R User Group is going live

Edmonton has made a name for itself as the City of Champions, The Gateway to the North and the most northern city in North America with a population of over 1

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