Monthly Archives: March 2012

di Roma

March 4, 2012
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di Roma

It has been a wonderful week in Roma, a mix of pleasant work and enjoyable free-time! I gave the ABC advanced course for the second time in a month so it did not require much in terms of preparation and there was a good sized audience with attentive (if too silent!) students and friends as

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Data visualization

March 4, 2012
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For those who have not read the seminal works of Tufte and Cleveland, please hang your heads in shame. To salvage some sense of self-worth, you can then head over to Solomon Messing’s blog where he is starting a series on data visualization based on ...

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Boxplots and Day of Week Effects

March 4, 2012
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Boxplots and Day of Week Effects

THIS BLOG DOES NOT CONSTITUTE INVESTMENT ADVICE. ACTING ON IT WILL MOST LIKELY BE DETRIMENTAL TO YOUR FINANCIAL HEALTH.After following some R-related quant finance blogs like Timely Portfolio, Systematic Investor or Quantitative tho...

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googleVis 0.2.15 is released: Improved geo and bubble charts

March 4, 2012
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googleVis 0.2.15 is released: Improved geo and bubble charts

The guys behind the Google Visualisation API don't seem to rest. On 22 February 2012 they released an update of their API. Google added options for a gradient colour axis to bubble chart and a magnifying glass to geo chart, which opens when the user ho...

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ggplot2 0.9.0 released

March 4, 2012
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This announcement was made by Hadley Wickham in the mailing list. ———————- # ggplot2 ggplot2 is a plotting system for R, based on the grammar of graphics, which tries to take the good parts of base and lattice graphics and avoid bad parts. It takes care of many of the fiddly details that make plotting a hassle (like drawing legends)...

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Interpretation of R-index

March 4, 2012
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Interpretation of R-index

Having introduced the R-index, it is time to look how it works. For this a simple example is sufficient. What happens if a product is different from another product. To make this at least slightly realistic, three products are needed. Two products will...

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Visualization series: Insight from Cleveland and Tufte on plotting numeric data by groups

March 4, 2012
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Visualization series: Insight from Cleveland and Tufte on plotting numeric data by groups

After my post on making dotplots with concise code using plyr and ggplot, I got an email from my dad who practices immigration law and runs a website with a variety of immigration resources and tools.  He pointed out that the … Continue reading →

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Spurious Regression illustrated

March 4, 2012
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Spurious Regression illustrated

Spurious Regression problem dates back to Yule (1926): “Why Do We Sometimes Get Nonsense Correlations between Time-series?”. Lets see what is the problem, and how can we fix it. I am using Morgan Stanley (MS) symbol for illustration, pre-crisis time … Continue reading →

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Setting the Default RNG Seed in R

March 4, 2012
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How to set the default seed for the RNG behind the runif(), sample() and other command? Well, there are several ways doing that (like setting .Random.seed directly), but as the documentation states, set.seed() is the recommended way to specify seeds.> ?set.seed> set.seed(0)> runif(1,0,1) 0.8966972> set.seed(0)> runif(1,0,1) 0.8966972> set.seed(0)> sample(1:10, 10) 9 3 10 5 ...

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My Pocket Change

March 4, 2012
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My Pocket Change

I'm playing around with some personal data collection, and using some cloud computing to visualize it. Following the directions in this blog post, I've written an R function which visualizes data it draws from a Google Docs spreadsheet, and uploaded it...

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