1955 search results for "Twitter"

Le Monde puzzle [38]

September 29, 2010
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Le Monde puzzle [38]

Since I have resumed my R class, I will restart my resolution of Le Monde mathematical puzzles…as they make good exercises for the class. The puzzle this week is not that exciting: Find the four non-zero different digits a,b,c,d such that abcd is equal to the sum of all two digit numbers made by picking

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Cooling stations. A UHI Hint

September 29, 2010
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Cooling stations. A UHI Hint

Update: google earth files in the box: Personally I like to look at things backwards. Why are cool sites cool? So download the kml or kmz file and you can tour 62 sites: All with 90 years of data or more. All with a cooling trend. And all “supposedly” urban. what do you see at

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Some Oddities with cooling stations

September 29, 2010
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Some Oddities with cooling stations

Now, that  the whole analysis has been moved to raster, I took some time to play around with a question that has interested  a couple of people. Cool stations. A while back when I was looking at ways of bounding uncertainties in the record I went on a hunt for the station that cooled the

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Galton & simulation

September 27, 2010
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Galton & simulation

Stephen Stigler has written a paper in the Journal of the Royal Statistical Society Series A on Francis Galton’s analysis of (his cousin) Charles Darwin’ Origin of Species, leading to nothing less than Bayesian analysis and accept-reject algorithms! “On September 10th, 1885, Francis Galton ushered in a new era of Statistical Enlightenment with an address

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Riemann, Langevin & Hamilton [reply]

September 27, 2010
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Riemann, Langevin & Hamilton [reply]

Here is a (prompt!) reply from Mark Girolami corresponding to the earlier post: In preparation for the Read Paper session next month at the RSS, our research group at CREST has collectively read the Girolami and Calderhead paper on Riemann manifold Langevin and Hamiltonian Monte Carlo methods and I hope we will again produce a

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Animation

September 25, 2010
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Animation

A couple hours work and we now have animations of the global anomalies: Created with the animation package in R.  The code examples were a bit terse about some of the details but after fiddling about I was able to get  the program to output an Html animation complete with java based playback controls. Write

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Visualising questionnaires

September 25, 2010
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Visualising questionnaires

Last week I was shown the results of a workplace happiness questionnaire. The plots were ripe for a makeover. Most obviously, the pointless 3D effect needs removing, and the colour scheme is badly chosen.

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Damn Close 5.0

September 24, 2010
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Damn Close 5.0

Code will be in the drop box in a bit, once I shower:   This is a wholesale replacement of previous versions, completely rewritten in raster. It will be the base going forward. All of the analysis routines will be rewritten using raster.  For time series functionality I will continue to use zoo as that

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Connecting to a MongoDB database from R using Java

September 24, 2010
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Connecting to a MongoDB database from R using Java

It would be nice if there were an R package, along the lines of RMySQL, for MongoDB. For now there is not – so, how best to get data from a MongoDB database into R? One option is to retrieve JSON via the MongoDB REST interface and parse it using the rjson package. Assuming, for

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Effective sample size

September 23, 2010
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Effective sample size

In the previous days I have received several emails asking for clarification of the effective sample size derivation in “Introducing Monte Carlo Methods with R” (Section 4.4, pp. 98-100). Formula (4.3) gives the Monte Carlo estimate of the variance of a self-normalised importance sampling estimator (note the change from the original version in Introducing Monte

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