Monthly Archives: August 2012

Careless comparison bites back (again)

August 6, 2012
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Careless comparison bites back (again)

When running stats labs I like to allocate a slightly different subset of data to each student, which acts as an incentive for people to do their own work (rather than copying the same results from a fellow student). We … Continue reading →

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Vim-R-plugin: Installation

August 6, 2012
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Vim-R-plugin: Installation

On Ubuntu 12.04, I took to the following steps to install Vim-R-plugin: First I had to install timux: sudo apt-get installl tmux Having already installed vim-pathogen, I used git to clone to install vim-r-plugin and vim-screen plugin, which is also … Continue reading →

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A bunch of R (and JAGS) scripts

August 6, 2012
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A bunch of R (and JAGS) scripts

I finally (nearly) got around to prepare the R code to replicate the examples in the book. I divided the examples by chapter and then linked to the R scripts and, for those involving Bayesian analysis, the associated JAGS models.At the moment, the scri...

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Predicting the 100m sprint: results

August 6, 2012
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Last week, Markus Gesmann used a log-linear model in R to predict the Olympic gold-medal winning 100m sprint time to be 9.68 seconds. The actual time was 9.63 seconds. Not bad! Meanwhile, the New York Times put Usuain Bolt's olympic record in context, comparing him in a virtual race with other gold medal-winners over the past century (via FlowingData).

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A heuristic enhancement of optimisation algorithm

August 6, 2012
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A heuristic enhancement of optimisation algorithm

The majority of the world’s problem deal with directly or indirectly some kind of optimisation. Instance of optimisation of resources or utility function can be seen our daily life. Here I am talking about standard optimisation problem in statistics, maximum … Continue reading →The post A heuristic enhancement of optimisation algorithm appeared first on Fiddling with...

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Provincial Monthly Rainfall of the Philippines from WORLDCLIM

August 6, 2012
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Provincial Monthly Rainfall of the Philippines from WORLDCLIM

Preparing for a future conference on climate change, I downloaded and extracted average monthly rainfall in the Philippines from worldclim.org. Using maptools, raster, and animation package in R, I produced an animation of average monthly rainfall of t...

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Adventures at My First JSM (Joint Statistical Meetings) #JSM2012

August 6, 2012
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Adventures at My First JSM (Joint Statistical Meetings) #JSM2012

During the past few decades that I have been in graduate school (no, not literally) I have boycotted JSM on the notion that “I am not a statistician.” Ok, I am a renegade statistician, a statistician by training. JSM 2012 was held in San Diego, CA, one of the best places to spend a week during the summer. This...

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Getting started with Sweave & knitr

August 6, 2012
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Getting started with Sweave & knitr

Cool woven artwork on the campus of Kansas University. The image is CC by Patrick Emerson I recently started to work with Sweave (by Friedrich Leisch)...

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Crawford-Howell (1998) t-test for case-control comparisons

August 6, 2012
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Crawford-Howell (1998) t-test for case-control comparisons

Cognitive neuropsychologists (like me) often need to compare a single case to a small control group, but the standard two-sample t-test does not work for this because the case is only one observation. Several different approaches have been proposed and in a new paper just published in Cortex, Crawford and Garthwaite (2012) demonstrate that the Crawford-Howell (1998) t-test...

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It is good to be explicit

August 6, 2012
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It is good to be explicit

Being careful not to repeat the year 1901 mistake, I set the TZ variable before I run R. I have the same set of data that I convert as follows: dates values date1 date2 and then plot plot( date1, values )plot( date2, values ) To my surprise I end up with the following two...

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