# Monthly Archives: November 2012

## Secret Santa

November 10, 2012
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On reddit somebody asked For n individuals, what's the probability that the last person to pick during a round of Secret Santa name picking, will pick their own name.. "With each person picking in turn, and re-picking if they pick out th...

## Back-testing Rules

November 10, 2012
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Nowadays there are many trading strategies shared online with reproducible, decent, results. Have you asked yourself, if the strategies are so profitable, why the author bother even sharing them, when the path to riches is clear – just implement the strategy and use it? There are people, of course, who are fascinated and challenged by

## Using R — .Call(“hello”)

November 9, 2012
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This entry is part 10 of 12 in the series Using RIn an introductory post on R APIs to C code, Calling C Code ‘Hello World!’, we explored the .C() function with some ‘Hello World!’ baby steps.  In this post …   read more ...

## Did the sun just explode? The last Dutch Book you’ll ever make

November 9, 2012
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$Did the sun just explode? The last Dutch Book you’ll ever make$

In today’s XKCD, a pair of (presumably) physicists are told by their neutrino detector that the sun has gone nova. Problem is, the machine rolls two dice and if they both come up six it lies, otherwise it tells the truth. The Frequentist reasons that the probability of obtaining this result if the sun had

## Exploring GAMs with Rosemary Hartman

November 9, 2012
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Today at Davis R Users’ Group, Rosemary Hartman took us through her work in progress fitting general additive models to organism presence/absence data. Below is her presentation and script. You can get the original script and data here Also, check the comments below for some discussion of other options for this type of analysis, such as...

## Video: How John Deere uses R

November 9, 2012
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Farming equipment manufacturer John Deere uses R, and in yesterday's webinar their manager of forecast analytics, Derek Hoffman, explained what they use it for: In the presentation, Derek gave a spirited argument of why R is critical for John Deere's operations: from forecasting demand for equipment, to forecasting crop yields (they produce forecasts for more than half the world's...

## Consuming R from SAP Mobile Platform

November 9, 2012
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Early this year, in March, I was visiting my team mates in SAP Labs Palo Alto, and my good friend a team mate Rui Nogueira asked to participate in his most excellent Technology Innovation Podcast show where we spoke about R and SAP HANA. By the end of ...

## Terrain effects on SUHI estimates

November 9, 2012
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Introduction Zhang and Imhoff (2010)  pdf here utilized NLCD impervious surface area (ISA), Olson biomes, and MODIS Land Surface temperature (LST) to estimate the magnitude of UHI in large cities across the US.  Peng  employed a   similar approach in studying 419 large cities ( population greater than 1m ) around world. Peng’s work suggests a limit or

## Video: Overlay Histogram in R (normal, density, another series)

November 9, 2012
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This video explains how to overlay histogram plots in R for 3 common cases: overlaying a histogram with a normal curve, overlaying a histogram with a density curve, and overlaying a histogram with a second data series plotted on a … Continue reading →Video: Overlay Histogram in R (normal, density, another series) is an article from